5,183 results on '"Charge separation"'
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2. Precisely Constructing Molecular Junctions in Hydrogen‐Bonded Organic Frameworks for Efficient Artificial Photosynthetic CO2 Reduction.
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Zhang, Yaqin, Li, Ping, Cui, Peng, Hu, Xunliang, Shu, Chang, Sun, Ruixue, Peng, Mengjie, Tan, Bien, and Wang, Xiaoyan
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ALTERNATIVE fuels , *STACKING interactions , *DENSITY functional theory , *PHOTOCATALYSTS , *CHARGE transfer - Abstract
The development of artificial photocatalysts to convert CO2 into renewable fuels and H2O into O2 is a complex and crucial task in the field of photosynthesis research. The current challenge is to enhance photogenerated charge separation, as well as to increase the oxidation capability of materials. Herein, a molecular junction‐type porphyrin‐based crystalline photocatalyst (Ni‐TCPP‐TPyP) was successfully self‐assembled by incorporating a nickel porphyrin complex as a reduction site and pyridyl porphyrin as an oxidation site via hydrogen bonding and π–π stacking interactions. The resulting material has a highly crystalline structure, and the formation of inherent molecular junctions can accelerate photogenerated charge separation and transport. Thus, Ni‐TCPP‐TPyP achieved an excellent CO production rate of 309.3 μmol g−1 h−1 (selectivity, ~100 %) without the use of any sacrificial agents, which is more than ten times greater than that of single‐component photocatalyst (Ni‐TCPP) and greater than that of the most organic photocatalysts. The structure‐function relationship was investigated by femtosecond transient absorption spectroscopy and density functional theory calculations. Our work provides new insight for designing efficient artificial photocatalysts, paving the way for the development of clean and renewable fuels through the conversion of CO2 using solar energy. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Metal Cocatalyst Engineering in Metal‐Semiconductor Hybrid Photocatalysts Achieves a Fivefold Enhancement of Hydrogen Evolution.
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Park, Bumjin, Park, Won‐Woo, Choi, Ji Yong, Bang, Kodong, Kim, Sungjoo, Choi, Ye‐Jin, Sul, Soohwan, Kwon, Oh‐Hoon, and Song, Hyunjoon
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HIGH performance computing , *QUANTUM efficiency , *ROUGH surfaces , *PHOTOCATALYSTS , *PHOTOCATALYSIS - Abstract
This study explores the optimal morphology of photochemical hydrogen evolution catalysts in a one‐dimensional system. Systematic engineering of metal tips on precisely defined CdSe@CdS dot‐in‐rods is conducted to exert control over morphology, composition, and both factors. The outcome yields an optimized configuration, a Au−Pt core‐shell structure with a rough Pt surface (Au@r‐Pt), which exhibits a remarkable fivefold increase in quantum efficiency, reaching 86 % at 455 nm and superior hydrogen evolution rates under visible and AM1.5 G irradiation conditions with prolonged stability. Kinetic investigations using photoelectrochemical and time‐resolved measurements demonstrate a greater extent and extended lifetime of the charge‐separated state on the tips as well as rapid water reduction kinetics on high‐energy surfaces. This approach sheds light on the critical role of cocatalysts in hybrid photocatalytic systems for achieving high performance. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Heterophase hexagonal/orthorhombic molybdenum trioxide nanorods for photocatalytic hydrogen production.
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Qian, Wanyue, Wang, Yunzhe, Liu, Liang, Yang, Yihan, Zhang, Guoxiang, Huang, Shuquan, and Yi, Jianjian
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PHASE transitions , *PHOTOCATALYSTS , *CHEMICAL structure , *HYDROGEN production , *TRIOXIDES - Abstract
Phase engineering plays a critical role in enhancing photocatalytic performance of metal oxides. Herein, we demonstrate the phase-selective synthesis of MoO 3 (hexagonal h-MoO 3 , orthorhombic α-MoO 3 , and their junction h/α-MoO 3) through controlled phase transitions by adjusting annealing conditions. As evidenced with photocatalytic hydrogen evolution reaction, h/α-MoO 3 (14.20 μmol/h) phase junction shows superior performance to either h-MoO 3 (9.62 μmol/h) or α-MoO 3 (11.31 μmol/h), with a hydrogen yield of 47.6% and 25.6% greater than that of h-MoO 3 and α-MoO 3 (Pt as cocatalyst), respectively. A systematic study of the chemical structure characterizations, photochemical tests, band structure analysis, and photocatalytic activity evaluation reveal that, the enhancement is attributed to the strong built-in electric field in the h/α-MoO 3 phase junction, which effectively facilitates charge separation. Our findings introduce a novel strategy for improving photocatalytic performance using phase engineering. [Display omitted] • MoO 3 with different phase structures can be synthesized by controllable phase transition for h-MoO 3 to α-MoO 3. • Heterophase h/α-MoO 3 demonstrates enhanced photocatalytic hydrogen production efficiency h-MoO 3 and α-MoO 3. • Phase junction induced built-in electric field can promote charge separation toward improved photocatalysis. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Excited Charge Transfer Promoted Electron Transfer in all Perylenediimide Derived, Wide‐Band Capturing Conjugates: A Mimicry of the Early Events of Natural Photosynthesis.
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Gutiérrez‐Vílchez, Ana M., Ileperuma, Chamari V., Navarro‐Pérez, Valeria, Karr, Paul A., Fernández‐Lázaro, Fernando, and D'Souza, Francis
- Abstract
Fundamental discoveries in electron transfer advance scientific and technological advancements. It is suggested that in plant and bacterial photosynthesis, the primary donor, a chlorophyll or bacteriochlorophyll dimer, forms an initial excited symmetry‐breaking charge transfer state (1CT*) upon photoexcitation that subsequently promotes sequential electron transfer (ET) events. This is unlike monomeric photosensitizer‐bearing donor‐acceptor dyads where ET occurs from the excited donor or acceptor (1D* or 1A*). In the present study, we successfully demonstrated the former photochemical event using an excited charge transfer molecule as a donor. Electron‐deficient perylenediimide (PDI) is functionalized with three electron‐rich piperidine entities at the bay positions, resulting in a far‐red emitting CT molecule (DCT). Further, this molecule is covalently linked to another PDI (APDI) carrying no substituents at the bay positions, resulting in wide‐band capturing DCT‐APDI conjugates. Selective excitation of the CT band of DCT in these conjugates leads to an initial 1DCT* that undergoes subsequent ET involving APDI, resulting in DCT+‐APDI− charge separation product (kCS~109 s−1). Conversely, when APDI was directly excited, ultrafast energy transfer (ENT) from 1APDI* to DCT (kENT~1011 s−1) followed by ET from 1DCT* to PDI is witnessed. While increasing solvent polarity improved kCS rates, for a given solvent, the magnitude of the kCS values was almost the same, irrespective of the excitation wavelengths. The present findings demonstrate ET from an initial CT state to an acceptor is key to understanding the intricate ET events in complex natural and bacterial photosynthetic systems possessing multiple redox‐ and photoactive entities. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Regulating the Photoisomerization of Covalent Organic Framework for Enhanced Photocatalytic Hydrogen Evolution†.
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Huang, Xingye and Guo, Jia
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HYDROGEN evolution reactions , *QUANTUM efficiency , *POLAR effects (Chemistry) , *PHOTOISOMERIZATION , *FUNCTIONAL groups - Abstract
Comprehensive Summary: Covalent organic framework (COF) is a desirable platform to tailor electronic properties for improving photocatalytic performances. However, the study on excited‐state configurations that determine photogenerated carrier dynamics has long been neglected. Herein, we concentrate on the molecular design of β‐ketoenamine‐linked COFs to drive their photoisomerization via the excited‐state intra‐molecular proton transfer (ESIPT), which can induce the partial keto‐to‐enol tautomerization and accordingly rearrange the photoinduced charge distribution. We demonstrate that the push‐pull electronic effect of functional side groups attached on the framework linkers is directly correlated with the ESIPT process. The phenylene linkers modified with electron‐withdrawing cyano‐groups reinforce the ESIPT‐induced tautomerization, leading to the in situ partial enolization for extended π‐conjugation and rearranged electron‐hole distribution. In contrast, the electron‐rich linkers limit the photoisomerization of COF and suppress the photoinduced electron accumulation. Thus, the maximum hydrogen evolution rate is achieved by the cyano‐modified COF, reaching as high as 162.72 mmol·g–1·h–1 with an apparent quantum efficiency of 13.44% at 475 nm, which is almost 11.5‐fold higher than those of analogous COFs with electron‐rich linkers. Our work opens up an avenue to control over the excited‐state structure transformation for enhanced photochemical applications. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Regulating the Photoisomerization of Covalent Organic Framework for Enhanced Photocatalytic Hydrogen Evolution†.
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Huang, Xingye and Guo, Jia
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HYDROGEN evolution reactions ,QUANTUM efficiency ,POLAR effects (Chemistry) ,PHOTOISOMERIZATION ,FUNCTIONAL groups - Abstract
Comprehensive Summary: Covalent organic framework (COF) is a desirable platform to tailor electronic properties for improving photocatalytic performances. However, the study on excited‐state configurations that determine photogenerated carrier dynamics has long been neglected. Herein, we concentrate on the molecular design of β‐ketoenamine‐linked COFs to drive their photoisomerization via the excited‐state intra‐molecular proton transfer (ESIPT), which can induce the partial keto‐to‐enol tautomerization and accordingly rearrange the photoinduced charge distribution. We demonstrate that the push‐pull electronic effect of functional side groups attached on the framework linkers is directly correlated with the ESIPT process. The phenylene linkers modified with electron‐withdrawing cyano‐groups reinforce the ESIPT‐induced tautomerization, leading to the in situ partial enolization for extended π‐conjugation and rearranged electron‐hole distribution. In contrast, the electron‐rich linkers limit the photoisomerization of COF and suppress the photoinduced electron accumulation. Thus, the maximum hydrogen evolution rate is achieved by the cyano‐modified COF, reaching as high as 162.72 mmol·g–1·h–1 with an apparent quantum efficiency of 13.44% at 475 nm, which is almost 11.5‐fold higher than those of analogous COFs with electron‐rich linkers. Our work opens up an avenue to control over the excited‐state structure transformation for enhanced photochemical applications. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Tailoring Carrier Dynamics of BiVO4 Photoanode via Dual Incorporation of Au and Co(OH)x Cooperative Modification for Photoelectrochemical Water Splitting.
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Chen, Xinchao, Li, Xiang, Peng, Youming, Yang, Hao, Tong, Yexiang, Balogun, M.‐Sadeeq, and Huang, Yongchao
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OXYGEN evolution reactions , *CHEMICAL kinetics , *SURFACE plasmon resonance , *CARBON offsetting , *ELECTRON density , *PHOTOELECTROCHEMISTRY , *CHARGE carriers , *PHOTOCATHODES - Abstract
Photoelectrochemical solar to hydrogen production is a promising way to achieve carbon neutrality, but severe charge recombination in photoanodes limits the conversion efficiency. Herein, Au nanoparticles and Co(OH)x co‐sensitized bismuth vanadate (BiVO4) to construct AuCo(OH)x/BiVO4 photoanode for significantly enhancing the performance of photoelectrochemical water splitting. This process significantly improves the bulk charge carrier separation efficiency, the surface kinetics of water oxidation, and the electron density of BiVO4 photoanode through Au surface plasmon resonance (SPR) and Co(OH)x oxygen evolution catalysts effect. Additionally, the enhancement of the *O and the *OOH generation accelerate the oxygen evolution reaction kinetics. Consequently, the constructed AuCo(OH)x/BiVO4 photoanode demonstrates an excellent photocurrent of 6.2 mA cm−2 at 1.23 V versus reversible hydrogen electrode and a stable continuous output within 42 h. This work contributes to developing high‐efficiency and high‐stability photoanodes for solar H2 production through SPR effect and oxygen evolution catalysts. [ABSTRACT FROM AUTHOR]
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- 2024
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9. The Role of Thermally Activated Charge Separation in Organic Solar Cells.
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Jain, Nakul, Jasiūnas, Rokas, Li, Xian'e, Zhang, Huotian, Fu, Jiehao, Zhang, Rui, Gang, Li, Fahlman, Mats, Gulbinas, Vidmantas, and Gao, Feng
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SOLAR cells , *ACTIVATION energy , *INVERSE relationships (Mathematics) - Abstract
In recent years, organic solar cells (OSCs) have shown high power efficiencies approaching 20%. However, the fundamental mechanisms of charge separation in these highly efficient devices have been a subject of intensive debates. Here, the charge separation efficiency (CSE) is extensively investigated across a wide range of blend systems with different energetic offsets. The findings unveil the temperature‐dependent nature of charge separation in low‐offset systems, emphasizing its significant contribution to the overall CSE. An intriguing inverse correlation between CSE and charge separation activation energy in relation to the offset is also observed. These results shed new light on the factors underlying the high CSE observed in the state‐of‐the‐art devices. [ABSTRACT FROM AUTHOR]
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- 2024
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10. A Core/Shell Bi2S3/BiVO4 Nanoarchitecture for Efficient Photoelectrochemical Water Oxidation.
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Xiong, Yuli, Zhang, Duo, Zhao, Xiaoxuan, Peng, Bo, Yu, Peng, and Cheng, Zhenxiang
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PHOTOELECTRON spectroscopy ,ELECTRIC fields ,OXIDATION kinetics ,OXIDATION of water ,ENERGY consumption - Abstract
The construction of nanostructured heterostructure is a potent strategy for achieving high‐performance photoelectrochemical (PEC) water splitting. Among these, constructing BiVO4‐based heterostructure stands out as a promising method for optimizing light‐harvesting efficiency and reducing severe charge recombination. Herein, we present a novel approach to fabricate a type II heterostructure of core/shell Bi2S3/BiVO4 using electrolytic deposition and successive ionic layer adsorption and reaction (SILAR) methods. We identify the type II heterostructure and the difference in fermi energy using UV‐Vis spectroscopy, X‐ray photoelectron spectroscopy, and PEC measurements. This redistribution of charges due to the fermi energy difference induces an interfacial built‐in electric field from BiVO4 to Bi2S3, reinforcing the photogenerated hole transfer kinetics from BiVO4 to Bi2S3. The Bi2S3/BiVO4 heterostructure exhibits a superior photocurrent (6.0 mA cm−2), enhanced charge separation efficiency (85 %), and higher open‐circuit photovoltage (350 mV). Additionally, the heterostructure displays a prolonged average lifetime of charge (1.63 ns), verifying this heterojunction could boost interfacial carriers' migration via an additional nonradiative quenching pathway. Furthermore, the lower photoluminescence (PL) intensity demonstrates the interfacial built‐in electric field is beneficial for boosting charge migration. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Strategy in Promoting Visible Light Absorption, Charge Separation, CO2 Adsorption and Proton Production for Efficient Photocatalytic CO2 Reduction with H2O.
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Zou, Jia‐Fu, Li, Sha, Liu, Peng, Zhao, Yiyi, Wang, Tingwei, Pan, Yun‐Xiang, and Yan, Xiaoliang
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VISIBLE spectra , *LIGHT absorption , *PHOTOCATALYSTS , *POTENTIAL energy , *RESEARCH personnel , *PHOTOREDUCTION - Abstract
Solar‐energy‐driven photocatalytic CO2 reduction by H2O to high‐valuable carbon‐containing chemicals has become one of the greatest concerns in both scientific and industrial communities, due to its potential in solving energy and environmental problems. However, efficiency of photocatalytic CO2 reduction by H2O is still far below the needs of large‐scale applications. The reduction efficiency is closely related to ability of photocatalysts in absorbing visible light which is the main part of sunlight (44 %), separating photogenerated electron‐hole pairs, adsorbing CO2 and producing protons for reducing CO2. Thus, photocatalysts with enhanced visible light absorption, electron‐hole separation, CO2 adsorption and proton production are highly desired. Herein, we aim to provide a picture of recent progresses in improving ability of photocatalysts in visible light absorption, electron‐hole separation, CO2 adsorption and proton production, and give an outlook for future researches associated with photocatalytic CO2 reduction by H2O. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Modulating built-in electric field via Bi-VO4-Fe interfacial bridges to enhance charge separation for efficient photoelectrochemical water splitting.
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Wang, Yingying, Huang, Jincheng, Chen, Yuxuan, Yang, Hao, Ye, Kai-Hang, and Huang, Yongchao
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ELECTRIC fields , *IRON-nickel alloys , *PHOTOCATHODES , *STANDARD hydrogen electrode , *HYDROGEN as fuel , *NICKEL oxide - Abstract
[Display omitted] Photoelectrochemical (PEC) water splitting on semiconductor electrodes is considered to be one of the important ways to produce clean and sustainable hydrogen fuel, which is a great help in solving energy and environmental problems. Bismuth vanadate (BiVO 4) as a promising photoanode for photoelectrochemical water splitting still suffers from poor charge separation efficiency and photo-induced self-corrosion. Herein, we develop heterojunction-rich photoanodes composed of BiVO 4 and iron vanadate (FeVO 4), coated with nickel iron oxide (NiFeO x /FeVO 4 /BiVO 4). The formation of the interface between BiVO 4 and FeVO 4 (Bi-VO 4 -Fe bridges) enhances the interfacial interaction, resulting in improved performance. Meanwhile, high-conductivity FeVO 4 and NiFeO x oxygen evolution co-catalysts effectively enhance bulk electron/hole separation, interface water's kinetics and photostability. Concurrently, the optimized NiFeO x /FeVO 4 /BiVO 4 possesses a remarkable photocurrent density of 5.59 mA/cm2 at 1.23 V versus reversible hydrogen electrode (vs RHE) under AM 1.5G (Air Mass 1.5 Global) simulated sunlight, accompanied by superior stability without any decreased of its photocurrent density after 14 h. This work not only reveals the crucial role of built-in electric field in BiVO 4 -based photoanode during PEC water splitting, but also provides a new guide to the design of efficient photoanode for PEC. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Bismuth Vacancies Induced Lattice Strain in BiVO4 Photoanodes Boosting Charge Separation For Water Oxidation.
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Liu, Boyan, Wang, Xin, Zhang, Yingjuan, Wan, Kang, Xu, Liangcheng, Ma, Siqing, Zhao, Ruoting, Wang, Songcan, and Huang, Wei
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GREEN fuels , *ENERGY levels (Quantum mechanics) , *STANDARD hydrogen electrode , *DENSITY functional theory , *OXIDATION of water , *PHOTOELECTROCHEMISTRY , *PHOTOCATHODES - Abstract
Photoelectrochemical (PEC) water splitting is a promising technology for green hydrogen production. However, severe charge recombination in the photoelectrode materials is one of the key obstacles to achieving high performance. Herein, a BiVO₄ photoanode with lattice strain (Str‐BVO) is constructed by generating Bi vacancies to promote charge separation in the bulk. The optimized Str‐BVO photoanode achieves a photocurrent density of 6.20 mA cm⁻2 at 1.23 V versus the reversible hydrogen electrode under AM 1.5 G illumination, with an impressive charge separation efficiency close to 100%. Systematical experiments and density functional theory reveal that the surface Bi vacancies induced strain causes the distortion of a small number of VO4 tetrahedra, which increases the antibonding state energy of most normal VO4 tetrahedra and creates more electronic vacancy states, thereby significantly promoting electron–hole separation. By surface loading with a FeNiOx co‐catalyst, the photoanode exhibits excellent PEC water‐splitting performance and stability. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Photophysical Properties and Photovoltaic Performance of Sensitizers with a Bipyrimidine Acceptor.
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Liu, Shiling, Gong, Kun, Li, Wei, Liu, Dongzhi, and Zhou, Xueqin
- Abstract
Molecular engineering is a crucial strategy for improving the photovoltaic performance of dye-sensitized solar cells (DSSCs). Despite the common use of the donor–π bridge–acceptor architecture in designing sensitizers, the underlying structure–performance relationship remains not fully understood. In this study, we synthesized and characterized three sensitizers: MOTP-Pyc, MOS
2 P-Pyc, and MOTS2 P-Pyc, all featuring a bipyrimidine acceptor. Absorption spectra, cyclic voltammetry, and transient photoluminescence spectra reveal a photo-induced electron transfer (PET) process in the excited sensitizers. Electron spin resonance spectroscopy confirmed the presence of charge-separated states. The varying donor and π-bridge structures among the three sensitizers led to differences in their conjugation effect, influencing light absorption abilities and PET processes and ultimately impacting the photovoltaic performance. Among the synthesized sensitizers, MOTP-Pyc demonstrated a DSSC efficiency of 3.04%. Introducing an additional thienothiophene block into the π-bridge improved the DSSC efficiency to 4.47% for MOTS2 P-Pyc. Conversely, replacing the phenyl group with a thienothiophene block reduced DSSC efficiency to 2.14% for MOS2 P-Pyc. Given the proton-accepting ability of the bipyrimidine module, we treated the dye-sensitized TiO2 photoanodes with hydroiodic acid (HI), significantly broadening the light absorption range. This treatment greatly enhanced the short-circuit current density of DSSCs owing to the enhanced electron-withdrawing ability of the acceptor. Consequently, the HI-treated MOTS2 P-Pyc-based DSSCs achieved the highest power conversion efficiency of 7.12%, comparable to that of the N719 dye at 7.09%. This work reveals the positive role of bipyrimidine in the design of organic sensitizers for DSSC applications. [ABSTRACT FROM AUTHOR]- Published
- 2024
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15. Interfacial Engineering of BiVO4/Bi2Mo2O9 Heterojunction Toward Photogenerated Carriers Anisotropic Transfer.
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Xiong, Yuli, Zhou, Yuting, Zhou, Nan, Peng, Bo, Wei, Xijun, and Wu, Zhimin
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SURFACE charges ,OXIDATION of water ,STANDARD hydrogen electrode ,WATER transfer ,SUBSTRATES (Materials science) - Abstract
Developing an advanced strategy to decrease the charge recombination of BiVO4 is a vital requirement to boost charge transfer for photoelectrochemical water oxidation. Herein, a type II BiVO4/Bi2Mo2O9 heterojunction is successfully synthesized on fluorine‐doped tin oxide substrate by successive ionic layer adsorption and reaction method. Thanks to the Fermi‐level energy difference of 275 mV between BiVO4 and Bi2Mo2O9, an outward built‐in electric filed pointing from Bi2Mo2O9 to BiVO4 is induced, which accelerates the directional flowing of photogenerated electron and hole. Such a unique design structure fastens the electron migration from BiVO4 to Bi2Mo2O9, and the holes will transfer to the surface to participate in water oxidation. The longer lifetime (9.2 ns) by time‐resolved transient photoluminescence signifies that the Bi2Mo2O9 can boost interfacial carriers' anisotropic migration; the surface charge transfer rate of BiVO4/Bi2Mo2O9 is up to 387.6 s−1 (1.4 V vs reversible hydrogen electrode (RHE)). The BiVO4/Bi2Mo2O9 heterojunction exhibits a remarkable charge separation efficiency of 64% and outstanding photocurrent density of 0.9 mA cm−2 at 1.23 V versus RHE. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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16. Nanohoops Favour Light‐Induced Energy Transfer over Charge Separation in Porphyrin/[10]CPP/Fullerene Rotaxanes.
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Schwer, Fabian, Zank, Simon, Freiberger, Markus, Steudel, Fabian M., Geue, Niklas, Ye, Lei, Barran, Perdita E., Drewello, Thomas, Guldi, Dirk M., and Delius, Max
- Abstract
[2]Rotaxanes offer unique opportunities for studying and modulating charge separation and energy transfer, because the mechanical bond allows the robust, yet spatially dynamic tethering of photoactive groups. In this work, we synthesized [2]rotaxane triads comprising a central (aza)[10]CPP⊃C60 bis‐adduct complex and two zinc porphyrin stoppers to address how the movable nanohoop affects light‐induced charge separation and energy transfer between the rotaxane subcomponents. We found that neither the parent nanohoop [10]CPP nor its electron‐deficient analogue aza[10]CPP actively participate in charge separation. In contrast, the nanohoops completely prevented through‐space charge separation. This result is likely due to supramolecular “shielding”, because charge separation was observed in the thread that acted as reference dyad. On the other hand, the suppression of electron transfer allowed the observation of energy transfer from the porphyrin triplet to the fullerene triplet state with a lifetime of ca. 25 μs. The presence of the interlocked nanohoops therefore leads to a dramatic switch between charge separation and energy transfer. We suggest that our results explain observations made by others in photovoltaic devices comprising nanohoops and may pave the way toward strategic uses of mechanically interlocked architectures in devices that feature (triplet) energy transfer. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Decoupled Crystallization and Particle Growth of BiVO4 via Rapid Thermal Process for Enhanced Charge Separation.
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Wang, Shujie, Liu, Bin, Wang, Qingzhen, Gong, Zichen, Zhang, Peng, Wang, Tuo, and Gong, Jinlong
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RAPID thermal processing , *FURNACES , *RATE of nucleation , *DIRECT-fired heaters , *OXIDATION of water - Abstract
BiVO4 is one of the most promising candidates for photoelectrochemical water oxidation. However, the poor crystallinity and short hole diffusion length limit its charge separation. One bottleneck stems from the contradiction between high crystallinity and small particles via conventional furnace heating processes. This paper describes the design and fabrication of BiVO4 photoanodes via rapid thermal process (RTP), rather than furnace heating, to decouple the constraints between nucleation, crystallization, and growth processes of BiVO4. The higher heating ramp rate of RTP compared with furnace heating promotes the fast diffusion of reactant molecules, which elevates the nucleation rate above the particle growth rate of BiVO4, leading to small particles with high crystallinity. Moreover, the ultra‐high heating temperature makes it possible to crystallize the small BiVO4 particle within a short time. Thus, a high crystallinity can be obtained for the RTP‐treated BiVO4 while maintaining small particle size, achieving a charge separation efficiency of up to 82%, 30% higher than that of furnace‐treated BiVO4 photoanode. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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18. Mechanistic insight into the synergy between platinum cluster and indium particle dual cocatalysts for enhanced photocatalytic water splitting.
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Zhang, Xinlei, Wu, Fei, Li, Guicun, Wang, Lei, Huang, Jianfeng, Song, Aili, Meng, Alan, and Li, Zhenjiang
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CLUSTERING of particles , *NITRIDES , *CHARGE carriers , *CLEAN energy , *CHARGE transfer , *SURFACE charges , *PLATINUM - Abstract
[Display omitted] • Dual-metal cocatalysts consisting of Pt NCs and In NPs were anchored on CN matrix. • The optimal Pt-In/CN exhibited an impressive photocatalytic H 2 production activity. • Pt NCs and In NPs as traps boosted the separation and migration of photogenerated charges. • Bimetallic cocatalysts regulated optimal adsorption behavior of H* intermediates for fast kinetics. Photocatalytic H 2 production is envisioned as a promising pillar of sustainable energy conversion system to address the energy crisis and environmental issues but still challenging. Herein, a strategy is proposed to design a dual-metal cocatalysts consisting of Pt nanoclusters (Pt NCs) and In nanoparticles (In NPs) anchored on polymeric carbon nitride (Pt-In/CN) for boosting photocatalytic water splitting. As expected, the designed Pt-In/CN photocatalyst exhibits an impressive H 2 production rate of 6.49 mmol·h−1·g−1 with an apparent quantum yield (AQY) of 33.56 % at 400 nm, which is 2.8- and 11.2-fold higher than those of the Pt/CN and In/CN, respectively. Combining experimental characterization with theoretical calculation demonstrates the synergistic mechanisms underpinning the enhanced photocatalytic activity. The Pt NCs and In NPs serve as photogenerated electron and hole trapping sites, respectively, which achieves the spatial separation of charge carriers and induces the polarized surface charge distribution, thus fostering optimal adsorption behavior of intermediates. More importantly, the p-block In NPs modulate the electronic microenvironment of Pt NCs to attenuate the adsorption behavior of H* intermediates for accelerated H 2 evolution kinetics. This work unveils a versatile strategy to regulate the electronic structures of dual-metal sites with synergy by establishing charge transfer mechanism for dual-metal cocatalysts. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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19. Enhanced piezocatalytic and piezo-photocatalytic dye degradation via S-scheme mechanism with photodeposited nickel oxide nanoparticles on PbBiO2Br nanosheets.
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Yuan, Shude, Liang, Xiaoya, Zheng, Yekang, Chu, Yuxin, Ren, Xujie, Zeng, Zhihao, Nan, Guangjun, Wu, Ying, and He, Yiming
- Subjects
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NICKEL oxides , *NICKEL oxide , *ENERGY harvesting , *NANOSTRUCTURED materials , *X-ray photoelectron spectroscopy , *P-type semiconductors , *PIEZOELECTRICITY - Abstract
[Display omitted] • Novel S-scheme NiO/PbBiO 2 Br composites are synthesized through a hybrid approach combining hydrothermal and photodeposition methods. • NiO/PbBiO 2 Br composites demonstrate dual energy harvesting capabilities from solar and vibration sources. • A synergistic effect between piezocatalysis and photocatalysis is observed in NiO/PbBiO 2 Br. • NiO/PbBiO 2 Br exhibits significantly increased photoactivity in RhB degradation. • Enhanced charge separation efficiency is achieved in NiO/PbBiO 2 Br via an S-scheme mechanism. The fabrication of an S-scheme heterojunction demonstrates as an efficient strategy for achieving efficient charge separation and enhancing catalytic activity of piezocatalysts. In this study, a new S-scheme heterojunction was fabricated on the PbBiO 2 Br surface through the photo-deposition of NiO nanoparticles. It was then employed in the piezoelectric catalytic degradation of Rhodamine B (RhB). The results demonstrate that the NiO/PbBiO 2 Br composite exhibits efficient performance in piezocatalytic RhB degradation. The optimal sample is the NiO/PbBiO 2 Br synthesized after 2 h of irradiation, achieving a RhB degradation rate of 3.11 h−1, which is 12.4 times higher than that of pure PbBiO 2 Br. Simultaneous exposure to visible light and ultrasound further increases in the RhB degradation rate, reaching 4.60 h−1, highlighting the synergistic effect of light and piezoelectricity in the NiO/PbBiO 2 Br composite. A comprehensive exploration of the charge migration mechanism at the NiO/PbBiO 2 Br heterojunction was undertaken through electrochemical analyses, theoretical calculations, and in-situ X-ray photoelectron spectroscopy analysis. The outcomes reveal that p-type semiconductor NiO and n -type semiconductor PbBiO 2 Br possess matching band structures, establishing an S-scheme heterojunction structure at their interface. Under the combined effects of band bending, interface electric fields, and Coulomb attraction, electrons and holes migrate and accumulate on the conduction band of PbBiO 2 Br and valence band of NiO, respectively, thereby achieving effective spatial separation of charge carriers. The catalyst's synergistic photo-piezoelectric catalysis effect can be ascribed to its role in promoting the generation and separation of charge carriers under both light irradiation and the piezoelectric field. The results of this investigation offer valuable insights into the development and production of catalytic materials that exhibit outstanding performance through the synergy of piezocatalysis and photocatalysis. [ABSTRACT FROM AUTHOR]
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- 2024
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20. High photocatalytic activity of g-C3N4/CdZnS/MoS2 heterojunction for hydrogen production.
- Author
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Lu, Ping, Zhao, Haixia, Li, Zhengmin, Chu, Mengzhu, Xie, Guangwen, Xie, Tian, and Jiang, Luhua
- Subjects
- *
SANDWICH construction (Materials) , *VISIBLE spectra , *LIGHT absorption , *ENERGY bands , *HYDROGEN production , *PHOTOCATALYSTS , *HETEROJUNCTIONS - Abstract
In an effort to improve the light absorption efficiency of the photocatalyst, g-C 3 N 4 nanosheets with visible light response have been prepared by roasting method, and the g-C 3 N 4 /CdZnS composite catalyst with 2D/0D architecture has been prepared by hydrothermal method after ultrasonic thinning. The g-C 3 N 4 /CdZnS/MoS 2 composite catalyst with 2D/0D architecture has been synthesized by secondary hydrothermal method. TEM analysis proves that a close heterogeneous interface has been formed between g-C 3 N 4 and CdZnS, and between CdZnS and MoS 2. The ultraviolet diffuse reflectance spectrum shows that MoS 2 has a wide light absorption range, which effectively enhances the light utilization ratio of the composite catalyst. The energy band structure diagram and photoelectrochemical test results show that a continuous stepped type II ternary heterojunction is formed among g-C 3 N 4 , CdZnS and MoS 2 , which promotes its separation of photogenerated charges. When the loading mass fraction of g-C 3 N 4 and MoS 2 is 4%, the hydrogen evolution rate of g-C 3 N 4 /CdZnS/MoS 2 composite catalyst is 57.02 mmol g−1 h−1 under visible light, which is exceeding 20% that of g-C 3 N 4 /CdZnS and 4.79 times and 44.9 times higher than that of CdZnS and g-C 3 N 4 , respectively. The two-dimensional structure of g-C 3 N 4 and MoS 2 significantly improves the stability of the composite catalyst. This work offers feasible ways for ternary heterogeneous photocatalyst construction. • The g-C 3 N 4 /CdZnS/MoS 2 composite catalyst was formed by secondary hydrothermal method. • A unique 2D/0D sandwich structure was formed between g-C 3 N 4 , CdZnS and MoS 2. • A close heterogeneous interface formed between g-C 3 N 4 and CdZnS, CdZnS and MoS 2. • The hydrogen evolution rate of g-C 3 N 4 /CdZnS/MoS 2 is 57.02 mmol g−1 h−1. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. Excited‐State Dynamics in Segregated Donor‐Acceptor Stacks Versus a Peri‐Bisdonor‐Acceptor System.
- Author
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Ramakrishnan, Remya, Madhu, Meera, Babu, Hruidya C., Sebastian, Ebin, and Hariharan, Mahesh
- Subjects
- *
RADICAL cations , *RADICAL anions , *MONOMERS , *PERYLENE , *CHROMOPHORES - Abstract
The investigation of impact of through‐space/through‐bond electronic interaction among chromophores on photoexcited‐state properties has immense potential owing to the distinct emergent photophysical pathways. Herein, the photoexcited‐state dynamics of homo‐sorted π‐stacked aggregates of a naphthalenemonoimide and perylene‐based acceptor‐donor (NI‐Pe) system and a fork‐shaped acceptor‐bisdonor (NI‐Pe2) system possessing integrally stacked peri‐substituted donors was examined. Femtosecond transient absorption (fsTA) spectra of NI‐Pe monomer recorded in chloroform displayed spectroscopic signatures of the singlet state of Pe; 1Pe*, the charge‐separated state; NI−⋅‐Pe+⋅, and the triplet state of Pe; 3Pe*. The examination of ultrafast excited‐state processes of NI‐Pe aggregate in chloroform revealed faster charge recombination (τCRa ${{\tau }_{CR}^{a}}$ =1.75 ns) than the corresponding monomer (τCRm ${{\tau }_{CR}^{m}}$ =2.46 ns) which was followed by observation of a broad structureless band attributed to an excimer‐like state. The fork‐shaped NI‐Pe2 displayed characteristic spectroscopic features of the NI radical anion (λmax~450 nm) and perylene dimer radical cation (λmax~520 nm) upon photoexcitation in non‐polar toluene solvent in the nanosecond transient absorption (nsTA) spectroscopy. The investigation highlights the significance of intrinsic close‐stacked arrangement of donors in ensuring a long‐lived photoinduced charge‐separated state (τCR ${{\tau }_{CR}}$ =1.35 μs) in non‐polar solvents via delocalization of radical cation between the donors. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Protruding‐Shaped Co Polarization Field on Ultrathin Covalent Triazine Framework Nanosheets for Efficient CO2 Photoreduction.
- Author
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Ma, Zhixue, Yin, Huang, Lyu, Pengbo, and Xu, Yuxi
- Subjects
- *
CHEMICAL kinetics , *CRYSTALLINE electric field , *VISIBLE spectra , *PHOTOCATALYSTS , *ELECTRIC fields - Abstract
Single‐atom photocatalysts (SAPs) engineered on various supports offer a promising pathway to efficiently convert CO2 into high‐valued products. However, most SAPs with near‐planar metal atom coordination structure suffer from low conversion efficiency, mainly due to the weak local polarized electric field which retards the reaction kinetics. Herein, this study reports for the first time a photocatalyst which simultaneously integrates protruding‐shaped Co single atom and strong polarization field in ultrathin crystalline covalent‐triazine‐framework nanosheets (donate as Co1/CTF‐NSs). Both experimental results and theoretical simulations demonstrated that giant local polarization field is successfully triggered on the Co1/CTF‐NSs, which induced directional charge migration and greatly promoted the separation of photogenerated carriers. The protruding‐Co centers enhanced the overlap between CO2 2p and Co 3d orbitals, thereby facilitating a strong affinity for CO2 adsorption. Furthermore, the local polarization fields between the protruding‐Co and CO2 drove the injection of a substantial number of electrons from Co 3d into CO2 π antibonding orbitals, leading to the effective activation and reduction of the CO2 molecules. Consequently, the as‐synthesized Co1/CTF‐NSs exhibited a remarkable CO production rate of 5391 µmol g−1 h−1 and a high selectivity (97.3%) under visible light irradiation, which represents one of the best molecular framework photocatalysts to date. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
23. Mechanism of Carrier Formation in P3HT-C 60 -PCBM Solar Cells.
- Author
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Tachikawa, Hiroto, Kawabata, Hiroshi, Abe, Shigeaki, and Watanabe, Ikuya
- Subjects
- *
SOLAR cells , *SEMICONDUCTOR materials , *EXCITED states , *CHARGE exchange , *TERNARY system - Abstract
Solar cells convert light energy directly into electricity using semiconductor materials. The ternary system, composed of poly(3-hexylthiophene) (P3HT), fullerene (C60), and phenyl-C61-butyric-acid-methyl-ester (PCBM), expressed as P3HT-C60-PCBM, is one of the most efficient organic solar cells. In the present study, the structures and electronic states of P3HT-C60-PCBM have been investigated by means of the density functional theory (DFT) method to shed light on the mechanism of charge separation in semiconductor materials. The thiophene hexamer was used as a model of P3HT. Five geometrical conformers were obtained as the C60-PCBM binary complexes. In the ternary system, P3HT wrapped around C60 in the stable structure of P3HT-C60-PCBM. The intermolecular distances for P3HT-(C60-PCBM) and (P3HT-C60)-PCBM were 3.255 and 2.885 Å, respectively. The binding energies of P3HT + (C60-PCBM) and (P3HT-C60) + PCBM were 27.2 and 19.1 kcal/mol, respectively. The charge transfer bands were found at the low-lying excited states of P3HT-C60-PCBM. These bands strongly correlated with the carrier separation and electron transfer in solar cells. The electronic states at the ground and excited states of P3HT-C60-PCBM were discussed on the basis of the calculated results. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Sliding dumbbell method to search for the CME in heavy-ion collisions.
- Author
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Aggarwal, Madan M, Attri, Anjali, Parmar, Sonia, Sharma, Anjali, and Singh, Jagbir
- Abstract
This study explores the chiral magnetic effect (CME) in ultra-relativistic heavy-ion collisions. The CME, observed as back-to-back charge separation along the magnetic field axis, is investigated using the newly developed sliding dumbbell method (SDM) applied to Au + Au events at a centre-of-mass energy s NN = 200 GeV generated by the AMPT model with string melting configuration. The CME-like signal is externally injected in the events by flipping charges of pairs of particles perpendicular to the reaction plane. The study reports a significant enhancement of the CME-sensitive 3-particle γ correlator in events with high back-to-back charge separation, in a given collision centrality. Additionally, a linear relationship is observed between the | γ | correlator for the same-sign charge pairs and positive charge asymmetry ( ⟨ A + ⟩ ) across the dumbbell in CME-enriched sub-samples. Furthermore, the fraction of CME in Δ γ (difference between the opposite and same sign γ correlators) is presented across different collision centralities having different percentages of externally injected CME-like signal. Overall, the research aims to understand and detect the CME through innovative experimental method and detailed analysis of the event structure. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. Highly controlled synthesis of symmetrically branched tripod and pentapod nanocrystals with enhanced photocatalytic performance.
- Author
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Luoshan, Meng-Dai, Yang, Yang, Dou, Zhen-Long, Zhang, Feng-Yuan, Yan, Hang-Yu, Zhou, Li, and Wang, Qu-Quan
- Subjects
- *
NANOCRYSTALS , *INTERSTITIAL hydrogen generation , *NANOPARTICLES , *OPTICAL properties , *SYMMETRY , *NANOSTRUCTURES - Abstract
Y-shaped AuCu tripods with three-fold symmetry from icosahedral seeds and star-shaped AuCu pentapods with five-fold symmetry from decahedral seeds are controlled synthesized. CdS nanocrystals and carrier-selective blocking layer of Ag 2 S are selectively deposited onto the sharp tips of AuCu tripods for achieving effective charge separation in AuCu-Ag 2 S-CdS nanohybrids with an optimized hydrogen evolution rate of 2182 μmol·g−1·h−1. [Display omitted] Anisotropic nanostructures with tunable optical properties induced by controllable size and symmetry have attracted much attention in many applications. Herein, we report a controlled synthesis of symmetrically branched AuCu alloyed nanocrystals. By varying Au:Cu atom ratio in precursor, Y-shaped tripods with three-fold symmetry and star-shaped pentapods with five-fold symmetry are synthesized, respectively. The growth mechanism of AuCu tripods from icosahedral seeds and AuCu pentapods from decahedral seeds is revealed. Aiming to excellent photocatalytic performance, CdS nanocrystals are controlled grown onto the sharp tips of AuCu tripods and pentapods. In addition, a carrier-selective blocking layer of Ag 2 S is introduced between AuCu and CdS, for achieving effective charge separation in AuCu-Ag 2 S-CdS nanohybrids. Through evaluating the photocatalytic performance by hydrogen generation experiments, the AuCu-Ag 2 S-CdS tripod nanocrystals exhibit an optimized hydrogen evolution rate of 2182 μmol·g−1·h−1. These findings will contribute greatly to the understanding of complex nanoparticle growth mechanism and provide a strategy for the design of anisotropic nanoalloys for widely photocatalytic applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Piezoelectric-enhanced n-TiO2/BaTiO3/p-TiO2 heterojunction for highly efficient photoelectrocatalysis.
- Author
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Minhua Ai, Zihang Peng, Xidi Li, Faryal Idrees, Xiangwen Zhang, Ji-Jun Zou, and Lun Pan
- Subjects
PIEZOELECTRIC materials ,TITANIUM dioxide ,BARIUM titanate ,HETEROJUNCTIONS ,ELECTROCATALYSIS - Abstract
Charge separation is critical for achieving efficient solar-to-hydrogen conversion, whereas piezoelectric-enhanced photoelectrochemical (PEC) systems can effectively modulate band bending and charge migration. Herein, we design an n-TiO2/BaTiO3/p-TiO2 (TBTm) heterojunction in which the piezoelectric BaTiO3 layer is sandwiched between n-TiO2 and p-TiO2. The built-in electric field of TBTm can provide a strong driving force to accelerate carrier separation and prolong carrier lifetime. Consequently, the TBT3 achieves a prominent photocurrent density, as high as 2.13 mA cm2 at 1.23 V versus reversible hydrogen electrode (RHE), which is 2.4- and 1.5-times higher than TiO2 and TiO2-- BaTiO3 heterojunction, respectively. Driven by mechanical deformation, the induced dipole polarization can further regulate built-in electric fields, and the piezoelectric photocurrent density of TBT3-800 is 2.84 times higher than TiO2 at 1.23 V vs. RHE due to the construction of piezoelectric-heterostructures. This work provides a piezoelectric polarization strategy for modulating the built-in electric field of heterojunction for PEC system. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. A comparative study for optimizing photocatalytic activity of TiO2-based composites with ZrO2, ZnO, Ta2O5, SnO, Fe2O3, and CuO additives
- Author
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I. Abdelfattah and A. M. El-Shamy
- Subjects
Photocatalysis ,Metal oxide composites ,Imazapyr ,Environmental remediation ,Charge separation ,Energy conservation ,Medicine ,Science - Abstract
Abstract Despite the widespread use of titanium dioxide (TiO2) in photocatalytic applications, its inherent limitations, such as low efficiency under visible light and rapid recombination of electron-hole pairs, hinder its effectiveness in environmental remediation. This study presents a comparative investigation of TiO2-based composites, including TiO2/ZrO2, ZnO, Ta2O3, SnO, Fe2O3, and CuO, aiming to assess their potential for enhancing photocatalytic applications. Photocatalysis holds promise in environmental remediation, water purification, and energy conversion, with TiO2 being a prominent photocatalyst. To improve efficiency and broaden applicability, various metal oxide composites have been explored. Composites were synthesized and characterized using techniques such as XRD, SEM, TEM, and zeta potential analysis to evaluate their structural and morphological properties. Photocatalytic performance was assessed by degrading herbicide Imazapyr under UV illumination. Results revealed that, the photo-activity of all prepared composites were more effective than the photo-activity of commercial hombikat UV-100. The photonic-efficiency is arranged according to the order TiO2/CuO > TiO2/SnO > TiO2/ZnO > TiO2/Ta2O3 > TiO2/ZrO2 > TiO2/Fe2O3 > Hombikat TiO2-UV100. All composites exhibited superior performance, attributed to enhanced light absorption and charge separation. The study underscores the potential of these composites for environmental remediation and energy conservation, offering valuable insights for the development of advanced photocatalysts.
- Published
- 2024
- Full Text
- View/download PDF
28. Nanoscale engineering of semiconductor photocatalysts boosting charge separation for solar-driven H2 production: Recent advances and future perspective
- Author
-
Khan Khakemin, Rehman Zia Ur, Yao Shanshan, Bajpai Om Prakash, Miotello Antonio, Nawaz Mohsan, Orlandi Michele, Khan Khalid Ali, Alanazi Abdulaziz A., and Zaki Magdi E. A.
- Subjects
nanoscale engineering ,charge separation ,solar drive hydrogen production ,Technology ,Chemical technology ,TP1-1185 ,Physical and theoretical chemistry ,QD450-801 - Abstract
Graphical illustration of various strategies of nanoscale engineering boosting charge separation in semiconductor photocatalysts for photocatalytic hydrogen production.
- Published
- 2024
- Full Text
- View/download PDF
29. Piezoelectric-enhanced n-TiO2/BaTiO3/p-TiO2 heterojunction for highly efficient photoelectrocatalysis
- Author
-
Minhua Ai, Zihang Peng, Xidi Li, Faryal Idrees, Xiangwen Zhang, Ji-Jun Zou, and Lun Pan
- Subjects
Photoelectrochemical ,Piezoelectric polarization ,Heterojunction ,Charge separation ,Renewable energy sources ,TJ807-830 ,Ecology ,QH540-549.5 - Abstract
Charge separation is critical for achieving efficient solar-to-hydrogen conversion, whereas piezoelectric-enhanced photoelectrochemical (PEC) systems can effectively modulate band bending and charge migration. Herein, we design an n-TiO2/BaTiO3/p-TiO2 (TBTm) heterojunction in which the piezoelectric BaTiO3 layer is sandwiched between n-TiO2 and p-TiO2. The built-in electric field of TBTm can provide a strong driving force to accelerate carrier separation and prolong carrier lifetime. Consequently, the TBT3 achieves a prominent photocurrent density, as high as 2.13 mA cm−2 at 1.23 V versus reversible hydrogen electrode (RHE), which is 2.4- and 1.5-times higher than TiO2 and TiO2–BaTiO3 heterojunction, respectively. Driven by mechanical deformation, the induced dipole polarization can further regulate built-in electric fields, and the piezoelectric photocurrent density of TBT3-800 is 2.84 times higher than TiO2 at 1.23 V vs. RHE due to the construction of piezoelectric-heterostructures. This work provides a piezoelectric polarization strategy for modulating the built-in electric field of heterojunction for PEC system.
- Published
- 2024
- Full Text
- View/download PDF
30. Non-metal inducing charge rearrangement in carbon nitride to promote photocatalytic hydrogen production.
- Author
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Wu, Guanyu, He, Zhiyu, Wang, Qiuheng, Wang, Haibo, Wang, Zeyu, Sun, Peipei, Mo, Zhao, Liu, Huanzhi, and Xu, Hui
- Subjects
NITRIDES ,HYDROGEN production ,ENERGY levels (Quantum mechanics) ,CHEMICAL energy ,THIN-walled structures ,HYDROGEN as fuel - Abstract
• Self-assembly synthesis of tubular carbon nitride co-modified with benzene ring and oxygen. • The tubular structure enhances light absorption and charge transfer. • Oxygen and benzene rings regulate the redox capacity and redox sites of carbon nitride, respectively. Photocatalytic hydrogen production technology offers a means of converting solar energy into chemical energy contained in hydrogen for human consumption. However, traditional photocatalysts restrict the progress of photocatalytic technology owing to the straightforward complexation of carriers and lack of active sites. Thus, in this work, the number of active sites and carrier separation efficiency have been significantly improved by non-metallic modification and modulation of the geometry of carbon nitride. It has been demonstrated that oxygen doping enhances the energy band structure of benzene-substituted O-doped g-CN nanotubes (BOCN). Oxygen, in conjunction with the benzene ring, creates redox energy level positions that are spatially separated. One-dimensional tubular structures synthesised by supramolecular self-assembly have a thin-walled structure capable of exposing more active sites. Additionally, the adsorption equilibrium of H
+ on the catalyst is further enhanced. The in-depth analysis of each component through experiments and theoretical calculations contributes to a reasonable photocatalytic mechanism for decomposing aquatic hydrogen. [Display omitted] [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
31. Coupling multifunctional ZnCoAl-layered double hydroxides on Ti-Fe2O3 photoanode for efficient photoelectrochemical water oxidation.
- Author
-
Cheng, Haiyang, Ba, Kaikai, Liu, Yunan, Lin, Yanhong, Wang, Dejun, and Xie, Tengfeng
- Subjects
- *
OXYGEN evolution reactions , *OXIDATION of water , *SURFACE charges , *OXIDATION kinetics , *CHARGE transfer , *PHOTOELECTROCHEMISTRY - Abstract
[Display omitted] • A novel ZnCoAl-LDH/Ti-Fe 2 O 3 photoanode is designed and constructed. • The ZnCoAl-LDH/Ti–Fe 2 O 3 photoanode achieved a photocurrent density of 3.51 mA/cm2 at 1.23 V vs. RHE. • The separation and transport behavior of photogenerated charges was investigated. • The synergistic effects among the three metals were revealed. The efficiency of photoelectrochemical (PEC) water splitting is hindered by the slow kinetics of the oxygen evolution reaction (OER). This study developed a composite photoanode for water oxidation by incorporating ternary LDHs (ZnCoAl-LDH) onto Ti-Fe 2 O 3 as a cocatalyst. The ZnCoAl-LDH/Ti–Fe 2 O 3 photoanode achieved a photocurrent density of 3.51 mA/cm2 at 1.23 V vs. RHE, which is 9.8 times higher than that of bare Ti-Fe 2 O 3. Through a series of characterizations, the synergistic effects among the three metals were revealed. Furthermore, the addition of Zn can induce the formation of more high-valent Co, increasing the conductivity of CoAl-LDH and significantly reducing the surface charge transfer resistance. These advantages significantly enhance the injection efficiency of ZnCoAl-LDH/Ti-Fe 2 O 3 (82 %), thereby accelerating the OER kinetics of Ti-Fe 2 O 3. Our work introduces new approaches for selecting photoelectrochemical cocatalysts and designing high-performance photoanodes for water splitting. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
32. Constructing S-scheme heterojunction Cs3Bi2Br9/BiOBr via in-situ partial conversion to boost photocatalytic N2 fixation.
- Author
-
Ren, An-Di, Liu, Zhao-Lei, Yuan, Su-Xian, Zhang, Min, and Lu, Tong-Bu
- Subjects
- *
CHARGE exchange , *ACTIVATION energy , *CHARGE transfer , *HETEROJUNCTIONS , *NANOCRYSTALS - Abstract
An in - situ partial conversion strategy is proposed and employed to successfully synthesize a lead-free halide perovskite-based S-scheme heterojunction of Cs 3 Bi 2 Br 9 /BiOBr, which exhibits swift transfer and separation of photogenerated carriers and thus significant improvement in photocatalytic N 2 reduction activity compared to traditional electrostatic self-assembled heterojunction. [Display omitted] The judicious construction of interfaces with swift charge communication to enhance the utilization efficiency of photogenerated carriers is a viable strategy for boosting the photocatalytic performance of heterojunctions. Herein, an in-situ partial conversion strategy is reported for decorating lead-free halide perovskite Cs 3 Bi 2 Br 9 nanocrystals onto BiOBr hollow nanotube, resulting in the formation of an S-scheme heterojunction Cs 3 Bi 2 Br 9 /BiOBr. This unique in-situ growth approach imparts a closely contacted interface to the Cs 3 Bi 2 Br 9 /BiOBr heterojunction, facilitating interfacial electron transfer and spatial charge separation compared to a counterpart (Cs 3 Bi 2 Br 9 :BiOBr) fabricated via traditional electrostatic self-assembly. Additionally, the establishment of an S-scheme charge transfer pathway preserves the robust redox capability of photogenerated carriers. Furthermore, the free electron transfer from Cs 3 Bi 2 Br 9 to BiOBr promotes the activation of the N N bond and diminishes the energy barrier associated with the rate-determining step in the N 2 reduction process. Consequently, the Cs 3 Bi 2 Br 9 /BiOBr heterojunction exhibits highly selective photocatalytic N 2 reduction to NH 3 (nearly 100 %) at a rate of 130 μmol g−1 h−1 under simulated sunlight (100 mW cm−2), surpassing BiOBr, Cs 3 Bi 2 Br 9 , and Cs 3 Bi 2 Br 9 :BiOBr by factors of 6, 4, and 2, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
33. Strong electron coupling effect of Zn-vacancy engineered S-scheme MnCdS/ZnS heterojunction derived from Metal-organic frameworks for highly efficient photocatalytic overall water splitting.
- Author
-
Shao, Yifan, Hao, Xuqiang, Deng, Wei, and Jin, Zhiliang
- Subjects
- *
INTERSTITIAL hydrogen generation , *BAND gaps , *DENSITY of states , *TURNOVER frequency (Catalysis) , *QUANTUM efficiency - Abstract
Zn-vacancy mediated S-scheme MnCdS/ZnS-V Zn composite derived from MnCdS/MOF-5 were successfully prepared by in-situ vulcanization of MOF-5 in a new-fashioned sacrificial reagent of Na 2 S/NaH 2 PO 2. Integrated the advantages of the defect engineering and S-scheme heterojunction, the excellent and stable photocatalytic overall water splitting activity with H 2 and O 2 evolution rate of 302.10 μmol g−1h−1 and 148.62 μmol g−1h−1 were obtained over 20% MnCdS/ZnS-V Zn which loaded Pt and Co 3 O 4 nanorods as cocatalysts. In the half-reaction experiments, the maximum H 2 evolution rate of 20% MnCdS/ZnS-V Zn is 19.72 mmol g−1h−1 with a notable AQE of 16.43% at 420 nm. [Display omitted] • V Zn -vacancy mediated S-scheme MnCdS/ZnS-V Zn derived from MnCdS/MOF-5. • The Zn-defects in the ZnS in favour of constructing S-scheme charge transfer path. • The maximum H 2 -production rate is achieved over 20% MnCdS/ZnS-V Zn with a notable AQE. • The Pt/20% MnCdS/ZnS-V Zn /3% Co 3 O 4 can split pure water into H 2 and O 2. • The S-scheme mechanism was confirmed by in-situ XPS, work function and EPR. Designing efficient sulfide photocatalysts for the simultaneous split water into H 2 and O 2 continue to be an arduous challenge. Herein, a Zn-vacancy mediated S-scheme MnCdS/ZnS-V Zn heterojunction derived from MnCdS/MOF-5 via in-situ vulcanization of MOF-5 in a new-fashioned sacrificial reagent of Na 2 S/NaH 2 PO 2 was fabricated. The presence of Zn vacancy (V Zn) was certified by TEM, XPS, EPR and PL results, which result in a new defect level in the band structure of ZnS. The S-scheme charge transfer path was established between MnCdS and ZnS-V Zn by V Zn vacancies, and the photocorrosion is depressed efficiently and a dramatic rise occurs on photocatalytic performance. The strong electron coupling effect of S-scheme heterojunction mechanism was confirmed via in-situ XPS, SPV, work function, and radicals test by EPR. The band gap and density of state about ZnS-V Zn and MnCdS are also calculated by the DFT. In HER semi-reaction, the strongest photocatalytic hydrogen generation rate of 20 % MnCdS/ZnS-V Zn is 394.4 μmol/h with a splendid apparent quantum efficiency of 16.43 % at 420 nm, and the turnover number (TON) is 98.6. The hydrogen production rate of 20 % MnCdS/ZnS-V Zn is drastically advanced by 123.25 times in contrast to the unadorned ZnS-V Zn. And superior photostability is also obtained. Prominently, the high-efficiency and steady photocatalytic overall water splitting rates of 5.7μmol/h (H 2) and 3.0μmol/h (O 2) were achieved over 20 % MnCdS/ZnS-V Zn with 1 % wt Pt and 5 % wt Co 3 O 4 nanorod as cocatalysts, and the photocatalytic stability was excellent. This research supplies neoteric insights for designing of highly efficient V Zn -mediated S-scheme sulfide photocatalysts to achieve pure water overall splitting with superior photocatalytic activity. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
34. Synergistic effect of Na doping and CoSe2 cocatalyst for enhanced photocatalytic hydrogen evolution performance of ZnIn2S4.
- Author
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Yuan, Shuya, Liu, Guowei, Zhang, Qingsheng, Liu, Taifeng, Yang, Jianjun, and Guan, Zhongjie
- Subjects
- *
ALKALI metal ions , *ELECTRONIC band structure , *CONDUCTION bands , *BAND gaps , *CONDUCTION electrons , *ALKALI metals - Abstract
The photocatalytic hydrogen evolution performance of ZnIn 2 S 4 is significantly enhanced by the synergy of Na doping and loading CoSe 2 cocatalyst. [Display omitted] • ZnIn 2 S 4 was modified by doping alkali metal ions and loading CoSe 2 cocatalyst for photocatalytic hydrogen production. • Alkali metal ions doping regulate the band gap and electronic structure of ZnIn 2 S 4 , thereby improving light absorption and charge separation. • Loading CoSe 2 cocatalyst further improves the charge separation and prolongs the lifetime of charge. • CoSe 2 /Na-ZnIn 2 S 4 shows much higher H 2 evolution activity than that of pure ZnIn 2 S 4. Element doping has been demonstrated as a useful strategy to regulate the band gap and electronic structure of photocatalyst for improving photocatalytic activity. Herein, ZnIn 2 S 4 (ZIS) nanosheets were doped with alkali metal ions (Li+, Na+ or K+) by a simple solution method. Experimental characterizations reveal that alkali metal ions doping reduce the band gap, raise the conduction band position, and improve surface hydrophilicity of ZIS. In addition, theoretical calculations show that Na doping increases the electron density at valence band maximum and surrounding S atom, which is conducive to produce more electrons and effective utilization of electrons, respectively. Benefited from above factors, Na-doped ZIS (Na-ZIS) shows the highest photocatalytic hydrogen evolution performance. Furthermore, CoSe 2 cocatalyst is loaded on the surface of Na-ZIS (CS/Na-ZIS), which further improve the charge separation and prolong the lifetime of charges. As a result, the optimized CS/Na-ZIS shows a H 2 evolution rate of 4525 μmol·g−1·h−1 with an apparent quantum efficiency of 27.5 % at 420 nm, which are much higher than that of pure ZIS. This study provides an in-depth understanding of the synergistic effect of Na doping and CoSe 2 cocatalyst in ameliorating photocatalytic activity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. In-plane heterostructures of transition metal dichalcogenide monolayers with enhanced charge separation and effective overall water splitting.
- Author
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Rehman, Shafiq Ur, Sun, Qihui, Wang, Junwei, Lv, Weiqiang, Khan, Azim, Liu, Yifan, Mahmood, Nasir, and Xian, Jian
- Subjects
- *
MOLECULAR dynamics , *DENSITY functional theory , *CHEMICAL bonds , *CONDUCTION bands , *CATALYTIC activity - Abstract
Finding a catalyst for overall water splitting (OWS) with robust thermodynamic stability and optimal electronic characteristics remains a significant challenge. This study investigates the thermodynamic stability and interfacial properties of zigzag and armchair MoS 2 /WS 2 in-plane heterostructures using ab-initio molecular dynamics (AIMD) and density functional theory (DFT) simulations. The motivation behind this research is to identify highly efficient and stable catalysts for OWS. The AIMD simulations confirm the thermodynamic stability of both heterostructures under working conditions. Notably, the zigzag MoS 2 /WS 2 in-plane heterostructure demonstrates superior charge separation efficiency, with larger conduction band (0.91 eV) and valence band (0.71 eV) offsets compared to the armchair configuration. The unique chemical bonding and type-II band alignment at the zigzag junction enhance charge transfer, resulting in excellent catalytic activities with ultralow overpotentials for oxygen (0.96 V) and hydrogen (0.3 V) evolution reactions at pH = 0. Additionally, the zigzag heterostructure achieves a high solar-to-hydrogen (STH) conversion efficiency of 12.29%, making it a promising candidate for practical applications in OWS. These findings contribute to the advancement of water splitting technology and encourage further research on in-plane interface formation among diverse materials. [Display omitted] • Electronic properties and stability studied via DFT and molecular dynamics simulations. • Photocatalytic characteristics of in-plane heterostructures thoroughly examined. • Zigzag in-plane heterostructure showed excellent catalytic activity and low overpotentials. • Zigzag in-plane heterostructure has 12.29% solar-to-hydrogen conversion efficiency. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Photoinduced Energy and Electron Transfer in a 'Two‐Point' Bound Panchromatic, Near‐Infrared‐Absorbing Bis‐styrylBODIPY(Zinc Porphyrin)2 – Fullerene Self‐Assembled Supramolecular Conjugate.
- Author
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Shao, Shuai, Gobeze, Habtom B., De Silva, Imesha W., Schaffner, Jacob, Verbeck, Guido, Karr, Paul A., and D'Souza, Francis
- Subjects
- *
ZINC porphyrins , *ENERGY transfer , *ENERGY harvesting , *CHARGE exchange , *CHARGE transfer , *PHOTOINDUCED electron transfer , *ELECTRON donors - Abstract
Structurally well‐defined self‐assembled supramolecular multi‐modular donor‐acceptor conjugates play a significant role in furthering our understanding of photoinduced energy and electron transfer events occurring in nature, e. g. in the antenna‐reaction centers of photosynthesis and their applications in light energy harvesting. However, building such multi‐modular systems capable of mimicking the early events of photosynthesis has been synthetically challenging, causing a major hurdle for its growth. Often, multi‐modularity is brought in by combining both covalent and noncovalent approaches. In the present study, we have developed such an approach wherein a π‐extended conjugated molecular cleft, two zinc(II)porphyrin bearing bisstyrylBODIPY (dyad, 1), has been synthesized. The binding of 1 via a 'two‐point' metal‐ligand coordination of a bis‐pyridyl fulleropyrrolidine (2), forming a stable self‐assembled supramolecular complex (1 : 2), has been established. The self‐assembled supramolecular complex has been fully characterized by a suite of physico‐chemical methods, including TD‐DFT studies. From the established energy diagram, both energy and electron transfer events were envisioned. In dyad 1, selective excitation of zinc(II)porphyrin leads to efficient singlet‐singlet excitation transfer to (bisstyrly)BODIPY with an energy transfer rate constant, kEnT of 2.56×1012 s−1. In complex 1 : 2, photoexcitation of zinc(II)porphyrin results in ultrafast photoinduced electron transfer with a charge separation rate constant, kCS of 2.83×1011 s−1, and a charge recombination rate constant, kCR of 2.51×109 s−1. For excitation at 730 nm corresponding to bisstyrylBODIPY, similar results are obtained, where a biexponential decay yielded estimated values of kCS 3.44×1011 s−1 and 2.97×1010 s−1, and a kCR value of 2.10×1010 s−1. The newly built self‐assembled supramolecular complex has been shown to successfully mimic the early events of the photosynthetic antenna‐reaction center events. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Adjusting the Covalency of Metal‐Oxygen Bonds in CuBi2O4 by Zn Cation Doping to Achieve Highly Efficient Photocathodes.
- Author
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Zhang, Yuheng, Xu, Yusheng, Zhang, Kejing, Li, Zhixue, Lin, Zeze, Hu, Junhua, and Song, Angang
- Abstract
Zn doped CuBi2O4 photocathodes are prepared by using a low‐cost solution‐based spray pyrolysis method. The doping of Zn in CuBi2O4 promotes the separation and migration of carriers and effectively increases the carrier density. Compared with CuBi2O4 alone, the photoelectrochemical activity of the Zn doped CuBi2O4 photoelectrode is improved with the photocurrent density of −0.56 mA/cm2 at 0.4 V vs. RHE. This improvement is due to the lower electronegativity of Zn, which leads to the covalent increase of Cu−O and Bi−O bonds in CuBi2O4, which limits the recombination of photogenerated electrons and holes and improves charge separation and transport. This study presents an innovative approach to enhance the charge separation efficiencies of photocathodes by implementing element doping strategies, which may contribute to further research on photocatalytic water splitting. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Novel A–D–A Type Naphthalenediimide Supramolecule for H2O2 Photosynthesis with Solar‐to‐Chemical Conversion 1.03%.
- Author
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Ji, Rong, Dong, Yuming, Sun, Xinyu, Li, Pengken, Zhang, Renbao, Pan, Chengsi, Zhao, Hui, and Zhu, Yongfa
- Subjects
- *
INTRAMOLECULAR charge transfer , *HYDROGEN peroxide , *HYDROGEN production , *ELECTRIC fields , *OXYGEN reduction - Abstract
Organic supermolecules have shown great promise for photocatalytic hydrogen peroxide (H2O2) production. However, the limitation of intramolecular charge separation efficiency is still a crucial scientific problem. In this study, a novel acceptor–donor–acceptor (A–D–A) type naphthalenediimide supramolecule (SA‐NDI) is successfully designed for overcoming fundamental issues in organic supermolecule. Composed of one electron‐rich core (naphthalenediimide) and two electron‐poor units (aminopyridine), the supramolecule possesses strong intramolecular charge transfer ability. Meanwhile, the SA‐NDI has an obviously stronger internal electric field, which is 2.83 times higher than that of D–A type supramolecule. The A–D–A type SA‐NDI efficiently accelerates charge separation, so that the intramolecular electron quickly migrates to the acceptor for a two‐electron oxygen reduction reaction. The SA‐NDI supramolecule shows excellent H2O2 accumulation ability (13.7 mm) and stable cyclic time above 120 h. Meanwhile, the catalyst exhibits a superior solar‐to‐chemical conversion efficiency of 1.03% under simulated solar irradiation. This work provides an entirely new idea to design an organic supramolecule with an efficient intramolecular charge transfer monomer. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. Fabrication of rGO‐Bridged TiO2/g‐C3N4 Z‐Scheme Nanocomposites via Pulsed Laser Ablation for Efficient Photocatalytic CO2 Reduction.
- Author
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Olatunji Waidi, Yusuf, Alkanad, Khaled, Abdullah Bajiri, Mohammed, Qahtan, Talal F., Al‐Aswad, A. H., Baroud, Turki N., Onaizi, Sagheer A, and Drmosh, Q. A.
- Abstract
Highly efficient photocatalysts can be fabricated using favorable charge transfer nanocomposite channel structures. This study adopted pulsed laser ablation in liquid (PLAL) to obtain rGO‐bridged TiO2/g‐C3N4 (rGO−TiO2/g‐C3N4) photocatalytic Z‐scheme without the need for noble metals. In addition to evaluating the resulting nanocomposite (comprising rGO nanosheets, TiO2 nanotubes, and g‐C3N4 nanosheets) CO2 reduction effectiveness, its chemical, morphological, structural, and optical characteristics were examined using various analytical techniques. The findings revealed a synergistic interaction between g‐C3N4 and TiO2, suggesting the presence of unique interfacial bonding, as well as enhanced visible light absorption. Notably, the ternary rGO−TiO2/g‐C3N4 Z‐scheme exhibits an excellent photocatalytic performance by photocatalytically converting CO2 into CO and CH4, with 81 % selectivity towards the CO and 1.91 % apparent quantum efficiency at 420 nm. Thus, the findings can pave the way for various Z‐scheme systems in wide photocatalytic applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Selective Segregation of Thermo‐Responsive Microgels via Microfluidic Technology.
- Author
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Sharma, Anjali, Rohne, Fabian, Vasquez‐Muñoz, Daniela, Jung, Se‐Hyeong, Lomadze, Nino, Pich, Andrij, Santer, Svetlana, and Bekir, Marek
- Subjects
- *
PHASE transitions , *TRANSITION temperature , *SHEAR flow , *BINARY mixtures , *MICROGELS - Abstract
Separation of equally sized particles distinguished solely by material properties remains still a very challenging task. Here a simple separation of differently charged, thermo‐responsive polymeric particles (for example microgels) but equal in size, via the combination of pressure‐driven microfluidic flow and precise temperature control is proposed. The separation principle relies on forcing thermo‐responsive microgels to undergo the volume phase transition during heating and therefore changing its size and correspondingly the change in drift along a pressure driven shear flow. Different thermo‐responsive particle types such as different grades of ionizable groups inside the polymer matrix have different temperature regions of volume phase transition temperature (VPTT). This enables selective control of collapsed versus swollen microgels, and accordingly, this physical principle provides a simple method for fractioning a binary mixture with at least one thermo‐responsive particle, which is achieved by elution times in the sense of particle chromatography. The concepts are visualized in experimental studies, with an intend to improve the purification strategy of the broad distribution of charged microgels into fractioning to more narrow distribution microgels distinguished solely by slight differences in net charge. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Adaptation processes in Halomicronema hongdechloris, an example of the light-induced optimization of the photosynthetic apparatus on hierarchical time scales.
- Author
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Schmitt, Franz-Josef and Friedrich, Thomas
- Subjects
PHOTOSYSTEMS ,ELECTRON transport ,REACTIVE oxygen species ,CHARGE exchange ,ENERGY transfer ,EXCITED states ,CHLOROPHYLL spectra ,CHARGE transfer - Abstract
Oxygenic photosynthesis in Halomicronema hongdechloris, one of a series of cyanobacteria producing red-shifted Chl f, is adapted to varying light conditions by a range of diverse processes acting over largely different time scales. Acclimation to far-red light (FRL) above 700 nm over several days is mirrored by reversible changes in the Chl f content. In several cyanobacteria that undergo FRL photoacclimation, Chl d and Chl f are directly involved in excitation energy transfer in the antenna system, form the primary donor in photosystem I (PSI), and are also involved in electron transfer within photosystem II (PSII), most probably at the Chl
D1 position, with efficient charge transfer happening with comparable kinetics to reaction centers containing Chl a. In H. hongdechloris, the formation of Chl f under FRL comes along with slow adaptive proteomic shifts like the rebuilding of the D1 complex on the time scale of days. On shorter time scales, much faster adaptation mechanisms exist involving the phycobilisomes (PBSs), which mainly contain allophycocyanin upon adaptation to FRL. Short illumination with white, blue, or red light leads to reactive oxygen species-driven mobilization of the PBSs on the time scale of seconds, in effect recoupling the PBSs with Chl f-containing PSII to re-establish efficient excitation energy transfer within minutes. In summary, H. hongdechloris reorganizes PSII to act as a molecular heat pump lifting excited states from Chl f to Chl a on the picosecond time scale in combination with a light-driven PBS reorganization acting on the time scale of seconds to minutes depending on the actual light conditions. Thus, structure-function relationships in photosynthetic energy and electron transport in H. hongdechloris including long-term adaptation processes cover 10-12 to 106 seconds, i.e., 18 orders of magnitude in time. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
42. Solar‐Driven Selective Oxidation Over Bismuth‐Based Semiconductors: From Prolific Catalysts to Diverse Reactions.
- Author
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Li, Shutao, Li, Yuanrui, and Huang, Hongwei
- Subjects
- *
COUPLING reactions (Chemistry) , *ALCOHOL oxidation , *ORGANIC synthesis , *OXIDATION , *SEMICONDUCTOR materials , *PHOTOCATALYTIC oxidation , *SEMICONDUCTORS - Abstract
Synthesis of organic compounds often necessitates rigorous reaction conditions or the involvement of hazardous oxidants, resulting in substantial energy consumption and considerable environmental damage. Photocatalytic selective oxidation represents a green and environmentally friendly way to obtain high‐value chemicals, which has developed rapidly in recent years. Bismuth‐based (Bi‐based) semiconductor materials have gained intense interest in selective organic synthesis due to their diverse crystal structures and compositions, tunable band structure, and outstanding photocatalytic performance. Herein, a systematic summary of the solar‐driven selective oxidation over varieties of Bi‐based semiconductors is provided. Initially, the reactive species involved in selective oxidation, Bi‐based materials widely used in photocatalytic selective oxidation, and the methods for synthesizing these Bi‐based materials are meticulously classified. Concerning their selective oxidation reactions, a variety of modification strategies, with a focus on the separation of photogenerated carriers and the regulation of reactive species is extensively documented. Highlights are the diverse applications and mechanism discussions of Bi‐based photocatalysts in the oxidation reactions, including alcohol oxidation, C─H bond activation, amine oxidation, and sulfide oxidation, as well as the coupling reactions with photoreduction. Finally, the future development prospects and challenges of Bi‐based photocatalysts in the field of selective oxidation is proposed, hoping to provide valuable insights and guidance for the design of photocatalysts for selective oxidation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. In-situ synthesis of sunlight-driven CuO-ZnO heterostructure photocatalyst for enhanced elimination of organic pollutants and CO2 reduction.
- Author
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Rasheed, Nada Ahmed, Faridh Fawzi, Omar, Almashhadani, Haidar Abdulkareem, Ismail, Ahmed, Ali, Sharafat, and Zahid, Muhammad
- Subjects
- *
PHOTODEGRADATION , *P-N heterojunctions , *WASTE recycling , *CONGO red (Staining dye) , *LIGHT absorption - Abstract
Removing hazardous organic pollutants, such as 4-nitrophenol (4-NP) and Congo red (CR) dyes from aqueous media and CO2 from the atmospheric medium remains a significant challenge. Herein, we report a facile in-situ synthetic approach for fabricating CuO-ZnO heterostructure photocatalysts through the surfactant-assisted co-precipitation method. The catalytic results demonstrate that the Cu1O-ZnO photocatalyst exhibits excellent activity under direct sunlight irradiation, owing to the heterostructure formation between the CuO and ZnO. The Cu1O-ZnO photocatalyst showed higher reaction rate constant (k) values of 0.20 min−1 for 4-NP and 0.09 min−1 for CR compared to previous reports. Additionally, efficient CO2 reduction was also achieved over Cu1O-ZnO photocatalyst. The optical and structural characterization results indicate that the improved photocatalytic reduction and degradation observed for the Cu1O-ZnO photocatalyst can be attributed to the strong synergistic interaction between p-type CuO and n-type ZnO and the construction of the p-n heterojunction. As a result, the absorption of visible light distinctly increased and inhibited the recombination rate of the photo-created electron-hole (e−/h+). Furthermore, the Cu1O-ZnO photocatalyst exhibited remarkable durability and recyclability, retaining high photoactivity (≥ 93%) after five cycles, demonstrating its potential for real-world applications in the photocatalytic reduction and degradation reactions under direct sunlight irradiation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Amino Acid Modified Hyper‐Cross‐Linked Polymer Enabling High‐efficient Photocatalytic Amines Oxidation Coupled with H2O2 Production.
- Author
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Gao, Wei, Fu, Yuyang, Nie, Xinhao, Zhao, Ying, Sun, Cuihong, Shang, Ningzhao, Cheng, Xiang, Gao, Shutao, Tian, Bin, and Wang, Chun
- Subjects
- *
PHOTOCATALYTIC oxidation , *TIME-dependent density functional theory , *POLYMERS , *REACTIVE oxygen species , *AMINO acids , *CHARGE exchange - Abstract
The simultaneous production of imine and hydrogen peroxide (H2O2) via photocatalytic aerobic amine oxidation is a bright way to obtain value added products, however, rapid recombination of photogenerated charge leads to low conversion efficiency and selectivity. Herein, a metal‐free amino acid modified hyper‐cross‐linked polymer (H3LP‐HCPs) photocatalyst was synthesized for photocatalytic amines oxidation by regulating the ratio of L‐phenylalanine (L‐Phe) and hexaphenylbenzene (Hex). The results showed that the H3LP‐HCPs photocatalyst with 1 : 3 molar ratio of L‐Phe and Hex achieves close to 100 % conversion efficiency and 100 % selectivity toward benzylamine oxidation under 455 nm blue LED lamp irradiation. Furthermore, a high yield of H2O2 (9.2 mmol ⋅ gcat−1 ⋅ h−1) was synchronously obtained in benzylamine oxidation. Experiments and time‐dependent density functional theory calculation results revealed that the N‐functional groups in H3LP‐HCPs photocatalyst not only remarkably broadens light‐response range, but also facilitates electrons transfer from L‐Phe to the Hex, thus accelerating photogenerated charge separation efficiency and the formation of reactive oxygen species (ROS). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Photocatalytic Production of Hydrogen Peroxide from Covalent-Organic-Framework-Based Materials: A Mini-Review.
- Author
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Meng, Jiayi, Huang, Yamei, Wang, Xinglin, Liao, Yifan, Zhang, Huihui, and Dai, Weilin
- Subjects
- *
HYDROGEN peroxide , *ENVIRONMENTAL protection , *OXIDIZING agents , *LIGHT absorption , *HYDROGEN production - Abstract
Hydrogen peroxide (H2O2) is one of the most environmentally friendly and versatile chemical oxidizing agents, with only O2 and H2O as reaction products. It is widely used in environmental protection, industrial production, and medical fields. At present, most of the industrial production of H2O2 adopts anthraquinone oxidation, but there are shortcomings such as pollution of the environment and large energy consumption. Covalent organic frameworks (COFs) are a class of porous crystalline materials formed by organic molecular building blocks connected by covalent bonds. The ordered conjugated structure of COFs not only facilitates the absorption of light energy but also promotes the transport of excited-state electrons. Therefore, the photochemical synthesis of H2O2 from water and oxygen using photocatalysts based on COFs as a green route has attracted much attention. In this review, we provide an overview of recent studies on COFs as photocatalysts and the different mechanisms involved in the photocatalytic production of hydrogen peroxide. Then, we summarize the various strategies to improve the performance. Finally, we outline the challenges and future directions of COFs in practical applications. This review highlights the potential and application prospects of COFs in the photochemical synthesis of H2O2, aiming to provide guidance for the design of COF-based catalysts and the optimization for photocatalytic production of H2O2, in order to promote scientific development and application in this field. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. 压电效应增强BaTiO3@TiO2 光催化析氢性能研究.
- Author
-
李明通 and 周建华
- Subjects
PIEZOELECTRIC composites ,CHARGE transfer ,ENERGY bands ,HYDROGEN production ,X-ray diffraction - Abstract
Copyright of Journal of Ceramics / Taoci Xuebao is the property of Journal of Ceramics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
47. In-situ one-step construction of poly(heptazine imide)/poly(triazine imide) heterojunctions for photocatalytic hydrogen evolution.
- Author
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Hui Li, Guoqiang Zhang, Peixin Zhang, and Hongwei Mi
- Subjects
QUANTUM efficiency ,LITHIUM chloride ,HETEROJUNCTIONS ,HYDROGEN production ,PHOTOCATALYSTS - Abstract
The construction of heterojunctions is challenging, requiring atomic-level contact and interface matching. Here, we have achieved atomic-level interfacial matching by constructing poly(heptazine imide)/poly(triazine imide) crystalline carbon nitride heterojunctions in an in-situ one-step method. The content of poly(triazine imide) in heterojunctions is positively related to the proportion of lithium chloride in potassium chloride and lithium chloride mixed-salts. The optimized heterojunction achieves an apparent quantum efficiency of 48.34% for photocatalytic hydrogen production at 420 nm, which is at a good level in polymeric carbon nitride photocatalysts. The proposed ion-thermal assisted heterojunction construction strategy contributes to the development of polymeric carbon nitride photocatalysts with high crystallization and high charge separation efficiency. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Achieving Seconds‐to‐Hours Duration‐Tunable Organic Long Persistent Luminescence from Carbon Dots‐Based Exciplex Systems by Energy Gaps Regulation†.
- Author
-
Xu, Yixuan, Jiang, Kai, Feng, Linger, Tong, Xinyuan, Zhou, Zuxu, Li, Fengshi, Zhang, Yi, Du, Jiaren, and Lin, Hengwei
- Subjects
- *
INFORMATION display systems , *BAND gaps , *DATA encryption , *EXCITED states , *EXCIMERS - Abstract
Comprehensive Summary: Duration‐tunable afterglow materials have garnered considerable attention in various applications. Herein, carbon dots (CDs)‐based long persistent luminescence (LPL) composites with a tunable duration in an ultrawide range of seconds‐to‐hours levels were designed and prepared for the first time. In contrast to the established CD‐based afterglow materials, we reported that CD‐based composites exhibit LPL in the form of exciplexes and long‐lived charge‐separated states, enabling the LPL to be prolonged from several seconds to over one hour, exceeding the typical regulation range (limited to 1 min). Further studies revealed that the relationship between the excited and charge‐transfer states of CDs plays a pivotal role in activating the LPL and regulating its duration. Furthermore, these composites exhibited high photoluminescence (PL) quantum yields of up to 60.63%, and their LPL was robust under ambient conditions, even in aqueous media. Their robust and superior LPL performance endows these composites with a strong competitive advantage in dynamic display systems, such as tags for time‐resolved data encryption and displays of the remaining time of takeaways. This study offers an approach to preparing CDs‐based LPL composites with tunable durations and may provide new insights for the development of rare‐earth‐free LPL materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Achieving Seconds‐to‐Hours Duration‐Tunable Organic Long Persistent Luminescence from Carbon Dots‐Based Exciplex Systems by Energy Gaps Regulation†.
- Author
-
Xu, Yixuan, Jiang, Kai, Feng, Linger, Tong, Xinyuan, Zhou, Zuxu, Li, Fengshi, Zhang, Yi, Du, Jiaren, and Lin, Hengwei
- Subjects
INFORMATION display systems ,BAND gaps ,DATA encryption ,EXCITED states ,EXCIMERS - Abstract
Comprehensive Summary: Duration‐tunable afterglow materials have garnered considerable attention in various applications. Herein, carbon dots (CDs)‐based long persistent luminescence (LPL) composites with a tunable duration in an ultrawide range of seconds‐to‐hours levels were designed and prepared for the first time. In contrast to the established CD‐based afterglow materials, we reported that CD‐based composites exhibit LPL in the form of exciplexes and long‐lived charge‐separated states, enabling the LPL to be prolonged from several seconds to over one hour, exceeding the typical regulation range (limited to 1 min). Further studies revealed that the relationship between the excited and charge‐transfer states of CDs plays a pivotal role in activating the LPL and regulating its duration. Furthermore, these composites exhibited high photoluminescence (PL) quantum yields of up to 60.63%, and their LPL was robust under ambient conditions, even in aqueous media. Their robust and superior LPL performance endows these composites with a strong competitive advantage in dynamic display systems, such as tags for time‐resolved data encryption and displays of the remaining time of takeaways. This study offers an approach to preparing CDs‐based LPL composites with tunable durations and may provide new insights for the development of rare‐earth‐free LPL materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Specificity of Photochemical Energy Conversion in Photosystem I from the Green Microalga Chlorella ohadii.
- Author
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Cherepanov, Dmitry A., Petrova, Anastasiya A., Fadeeva, Mariya S., Gostev, Fedor E., Shelaev, Ivan V., Nadtochenko, Victor A., and Semenov, Alexey Yu.
- Subjects
- *
PHOTOSYSTEMS , *ENERGY conversion , *CHLORELLA , *RADICAL ions , *CHLAMYDOMONAS reinhardtii , *CHLORELLA vulgaris , *CHLAMYDOMONAS - Abstract
Primary excitation energy transfer and charge separation in photosystem I (PSI) from the extremophile desert green alga Chlorella ohadii grown in low light were studied using broadband femtosecond pump-probe spectroscopy in the spectral range from 400 to 850 nm and in the time range from 50 fs to 500 ps. Photochemical reactions were induced by the excitation into the blue and red edges of the chlorophyll Qy absorption band and compared with similar processes in PSI from the cyanobacterium Synechocystis sp. PCC 6803. When PSI from C. ohadii was excited at 660 nm, the processes of energy redistribution in the light-harvesting antenna complex were observed within a time interval of up to 25 ps, while formation of the stable radical ion pair P700+A1− was kinetically heterogeneous with characteristic times of 25 and 120 ps. When PSI was excited into the red edge of the Qy band at 715 nm, primary charge separation reactions occurred within the time range of 7 ps in half of the complexes. In the remaining complexes, formation of the radical ion pair P700+A1− was limited by the energy transfer and occurred with a characteristic time of 70 ps. Similar photochemical reactions in PSI from Synechocystis 6803 were significantly faster: upon excitation at 680 nm, formation of the primary radical ion pairs occurred with a time of 3 ps in ~30% complexes. Excitation at 720 nm resulted in kinetically unresolvable ultrafast primary charge separation in 50% complexes, and subsequent formation of P700+A1− was observed within 25 ps. The photodynamics of PSI from C. ohadii was noticeably similar to the excitation energy transfer and charge separation in PSI from the microalga Chlamydomonas reinhardtii; however, the dynamics of energy transfer in C. ohadii PSI also included slower components. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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