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285 results on '"Pan, Chengsi"'

31. Effective H2O2 Photosynthesis in Gas–Liquid–Solid Triphase System with Self‐Floating Conjugated Organic Polymers.

Author

Guo, Yingxin, Dong, Yuming, Liu, Bing, Ni, Bangqing, Pan, Chengsi, Zhang, Jiawei, Zhao, Hui, Wang, Guangli, and Zhu, Yongfa

Subjects
SUSTAINABILITY, PHOTOREDUCTION, SUSTAINABLE construction, OXYGEN reduction, MASS transfer, CONJUGATED polymers
Abstract

Solar‐driven photocatalytic oxygen reduction is a promising pathway for sustainable hydrogen peroxide (H2O2) production. However, limited O2 diffusion and low selectivity in the two‐electron oxygen reduction reaction hinder its practical application. Here, a novel conjugated organic polymer material (conjugated triazine‐thiophene polymer, CTTP) based on triazine and thiophene, integrating a favorable mass transfer structure with competent catalytic centers is presented for the first time. Remarkably, under the gas–liquid–solid triphase condition, the self‐floating CTTP can rapidly capture gaseous oxygen, reducing it to superoxide radicals and transferring them to the reaction interface, drastically enhancing H2O2 yield. An excellent H2O2 concentration of 1.85 mm g−1 h−1 is achieved in a triphase system, representing a remarkable 14‐fold improvement compared to the liquid and solid phase reaction. Interestingly, the triphase system based on CTTP demonstrates the potential for large‐scale H2O2 production under 8 h of sunlight irradiation, reaching 293 ppm day−1 m−2. This work opens up a new avenue for the construction of sustainable H2O2 production systems and may stimulate future related research. [ABSTRACT FROM AUTHOR]

Published
2024
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39. Edge-Confined Rh2/MoS2Dual-Atom Catalyst for Selective Activation of Nitro Group to Amino Group at Room Temperature

Author

Zhao, Yi, Sun, Xue, Gu, Qingqing, Wang, Dong, Yang, Bing, Xu, Jing, Zhang, Ying, Pan, Chengsi, Zhu, Yongfa, and Lou, Yang

Abstract

Selective hydrogenation of nitroarenes to produce functionalized anilines is highly important to synthesize fine and bulk chemicals, but it remains challenging to achieve high selectivity at room temperature. Here, we report that a steric-confinement Rh dual atom catalyst is constructed by anchoring dual Rh atoms on the edge Mo vacancies of thin-layered MoS2nanosheets (Rh2/MoS2dual atom catalyst), which shows excellent catalytic conversion (100%) and selectivity (100%) for the selective hydrogenation of a family of nitroarene derivatives to functionalized anilines at room temperature. Extensive experimental characterizations and theoretical calculations indicate that the steric-confinement Rh2atoms, maintaining an exact metal–metal separation of 3.5 Å, facilitate spatially matched adsorption of the nitro group through a bidentate configuration. This significantly enhances the reactivity of nitro groups and drives the selective synthesis of functionalized anilines. The approach of employing bimetallic atoms to construct edge-confined active sites, as reported in this study, paves the way to develop highly selective catalysts for the targeted hydrogenation of nitroarenes.

Published
2024
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40. Boosting Undergraduate Research Skill through Synthesis and Catalytic Applications of Two-Dimensional MoS2in Selective Hydrogenation of Maleic Anhydride

Author

Xu, Jingwen, Xu, Jing, Zhang, Ying, Pan, Chengsi, Zhang, Jiawei, and Lou, Yang

Abstract

The essence of university courses lies in their scientific rigor, while the joy of learning serves as a motivating force. With this in mind, a comparative experiment was designed to investigate the catalytic role of phase configurations of two-dimensional MoS2(2D MoS2) in maleic anhydride (MAH) selective hydrogenation to succinic anhydride (SA). This experiment was tailored for senior undergraduates majoring in energy, materials science, and chemical engineering. Through the analysis of hydrogen temperature-programmed reduction (H2-TPR), Raman, and X-ray diffraction (XRD) data, the students thoroughly explored the structural information and chemical properties of synthesized 2D MoS2. The characterization and kinetic results revealed a linear relationship between the specific reaction rate and the concentration of 1T-MoS2, affirming the superior intrinsic activity of 1T-MoS2for MAH selective hydrogenation to SA. Following this comparative laboratory experiment, the students gained insight into the principles and processes of selective hydrogenation, learned about catalyst preparation and characterization methods, and developed scientific thinking skills for solving practical problems. Our comprehensive experiments are instrumental in enhancing students’ experimental skills and their ability to tackle practical problems using interdisciplinary knowledge.

Published
2024
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41. Novel A–D–A Type Naphthalenediimide Supramolecule for H2O2 Photosynthesis with Solar‐to‐Chemical Conversion 1.03%.

Author

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
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43. A photocatalytic redox cycle over a polyimide catalyst drives efficient solar-to-H2O2 conversion.

Author

Chi, Wenwen, Dong, Yuming, Liu, Bing, Pan, Chengsi, Zhang, Jiawei, Zhao, Hui, Zhu, Yongfa, and Liu, Zeyu

Subjects
RADICAL anions, CARBONYL group, OXIDATION-reduction reaction, ACTIVATION energy, PHOTOCATALYSTS, POLYIMIDES, OXYGEN reduction
Abstract

Circumventing the conventional two-electron oxygen reduction pathway remains a great problem in enhancing the efficiency of H2O2 photosynthesis. A promising approach to achieve outstanding photocatalytic activity involves the utilization of redox intermediates. Here, we engineer a polyimide aerogel photocatalyst with photoreductive carbonyl groups for non-sacrificial H2O2 production. Under photoexcitation, carbonyl groups on the photocatalyst surface are reduced, forming an anion radical intermediate. The produced intermediate is oxidized by O2 to produce H2O2 and subsequently restores the carbonyl group. The high catalytic efficiency is ascribed to a photocatalytic redox cycle mediated by the radical anion, which not only promotes oxygen adsorption but also lowers the energy barrier of O2 reduction reaction for H2O2 generation. An apparent quantum yield of 14.28% at 420 ± 10 nm with a solar-to-chemical conversion efficiency of 0.92% is achieved. Moreover, we demonstrate that a mere 0.5 m2 self-supported polyimide aerogel exposed to natural sunlight for 6 h yields significant H2O2 production of 34.3 mmol m−2. The photocatalytic redox cycle mediated by the anion radical intermediate promotes oxygen adsorption and lowers the energy barrier of O2 reduction reaction, thereby significantly improving the efficiency of H2O2 photosynthesis. [ABSTRACT FROM AUTHOR]

Published
2024
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45. Balanced generation of holes and superoxide radicals on Bi25CoO40 sillenite photocatalysts for rapidly synergetic degradation of quinolone antibiotics

Author

Sun, Hao, primary, Wang, Chen, additional, Shao, Yunhang, additional, Zhang, Yaning, additional, Chen, Chaofeng, additional, Liu, Hongyan, additional, Dou, Shuai, additional, Xu, Jing, additional, Zhang, Ying, additional, Lou, Yang, additional, Wang, Hui, additional, Zhu, Yongfa, additional, and Pan, Chengsi, additional

Published
2024
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50. Enhancement of H2O2generation rate in porphyrin photocatalysts viacrystal facets regulation to create strong internal electric field

Author

Shao, Yunhang, Zhang, Yaning, Chen, Chaofeng, Dou, Shuai, Lou, Yang, Dong, Yuming, Zhu, Yongfa, and Pan, Chengsi

Abstract

Three TCPP porphyrin-based nanosheet photocatalysts with exposed (400), (022), and (020) planes were synthesized using a dissolution-recrystallization method in a mixture of water and tetrahydrofuran (THF), methanol (MeOH), and ethylene glycol (EG). The TCPP photocatalyst with the exposed (400) surface exhibited the highest H2O2production rate of 29.33 mmol L−1h−1g−1from only H2O and O2, surpassing the rates observed for ones with exposed (022) and (020) surfaces by factors of 2.7 and 4.1, respectively, and 1.3 times as that of the reported TCPP prepared by a base/acid self-assembling method. This enhancement can be attributed to the strong internal electric field and high carboxyl group content on the (400) surface, which hindered rapid charge recombination and facilitated challenging water oxidation. Hence, successful manipulation of porphyrin exposure to robust IEF planes enhances the photocatalytic activity of the system and provides valuable insights for the design and development of more efficient organic photocatalysts.

Published
2024
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