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Modulating the energy barrier of reaction intermediates to surmount sluggish kinetics is an utterly intriguing strategy for amplifying the oxygen reduction reaction. Herein, a Cu 3 P/CoP hybrid is incorporated on hollow porous N-doped carbon nanospheres via dopamine self-polymerization and high-temperature treatment. The resultant Cu 3 P/CoP@NC showcases a favorable mass activity of 4.41 mA mg -1 and a kinetic current density of 2.38 mA cm -2 . Strikingly, the catalyst endows the aqueous Zn-air battery (ZAB) with a large power density of 209.0 mW cm -2 , superb cyclability over 317 h, and promising application prospects in flexible ZAB. Theoretical simulations reveal that Cu functions as a modulator to modify the free energy of intermediates and adsorbs the O 2 on the Co sites, hence rushing the reaction kinetics. The open and hydrophilic hollow spherical mesoporous structure provides unimpeded channels for reactant diffusion and electrolyte penetration, whereas the exposed inner and outer surfaces can confer a plethora of accessible actives sites. This research establishes a feasible design concept to tune catalytic activity for non-noble metal materials by construction of a rational nanoframework.

2D metal-organic frameworks (MOFs) have emerged as potential candidates for electrocatalytic oxygen evolution reactions (OER) due to their inherent properties like abundant coordination unsaturated active sites and efficient charge transfer. Herein, a versatile and massively synthesizable self-etching assembly strategy wherein nickel-iron foam (NFF) acts as a substrate and a metal ion source. Specifically, by etching the nickel-iron foam (NFF) surface using ligands and solvents, Ni/Fe metal ions are activated and subsequently reacted under hydrothermal conditions, resulting in the formation of self-supporting nanosheet arrays, eliminating the need for external metal salts. The obtained 33 % NiFeMOF/NFF exhibits remarkable OER performance with ultra-low overpotentials of 188/231 mV at 10/100 mA cm -2 , respectively, outperforming most recently reported catalysts. Besides, the built 33 % NiFeMOF/NFF (+) ||Pt/C (-) electrolyzer presents low cell voltages of 1.55/1.83 V at 10/100 mA cm -2 , superior to the benchmark RuO 2 (+) ||Pt/C (-) , implying good industrialization prospects. The excellent catalytic activity stems from the modulation of the electronic spin state of the Ni active site by the introduction of Fe, which facilitates the adsorption process of oxygen-containing intermediates and thus enhances the OER activity. This innovative approach offers a promising pathway for commercial-scale sustainable energy solutions., (© 2024 Wiley-VCH GmbH.)

Doping metals and constructing heterostructures are pivotal strategies to enhance the electrocatalytic activity of metal-organic frameworks (MOFs). Nevertheless, effectively designing MOF-based catalysts that incorporate both doping and multiphase interfaces poses a significant challenge. In this study, a one-step Co-doped and Co 3 O 4 -modified Ni-MOF catalyst (named Ni NDC-Co/CP) with a thickness of approximately 5.0 nm was synthesized by a solvothermal-assisted etching growth strategy. Studies indicate that the formation of the Co-O-Ni-O-Co bond in Ni NDC-Co/CP was found to facilitate charge density redistribution more effectively than the Co-O-Ni bimetallic synergistic effect in NiCo NDC/CP. The designating Ni NDC-Co/CP achieved superior oxygen evolution reaction (OER) activity (245 mV @ 10 mA cm -2 ) and robust long stability (100 h @ 100 mA cm -2 ) in 1.0 M KOH. Furthermore, the Ni NDC-Co/CP (+) ||Pt/C/CP (-) displays pregnant overall water splitting performance, achieving a current density of 10 mA cm -2 at an ultralow voltage of 1.52 V, which is significantly lower than that of commercial electrolyzer using Pt/C and IrO 2 electrode materials. In situ Raman spectroscopy elucidated the transformation of Ni NDC-Co to Ni(Co)OOH under an electric field. This study introduces a novel approach for the rational design of MOF-based OER electrocatalysts.

Bimetallic metal-organic framework (BMOF) exhibits better electrocatalytic performance than mono-MOF, but deciphering the precise anchoring of foreign atoms and revealing the underlying mechanisms at the atomic level remains a major challenge. Herein, a novel binuclear NiFe-MOF with precise anchoring of Fe sites is synthesized. The low-crystallinity (LC)-NiFe 0.33 -MOF exhibited abundant unsaturated active sites and demonstrated excellent electrocatalytic oxygen evolution reaction (OER) performance. It achieved an ultralow overpotential of 230 mV at 10 mA cm -2 and a Tafel slope of 41 mV dec -1 . Using a combination of modulating crystallinity, X-ray absorption spectroscopy, and theoretical calculations, the accurate metal sequence of BMOF and the synergistic effect of the active sites are identified, revealing that the adjacent active site plays a significant role in regulating the catalytic performance of the endmost active site. The proposed model of BMOF electrocatalysts facilitates the investigation of efficient OER electrocatalysts and the related catalytic mechanisms., (© 2023 Wiley-VCH GmbH.)

The effective defect and interface coupling are pivotal for the promotion of the catalytic activity for the oxygen evolution reaction. Herein, we report novel hybrid nanosheets with sulfur vacancies composed of FeS 2 and Cu 39 S 28 grown on Cu foam (V s -FeS 2 /Cu 39 S 28 ). The optimal V s -FeS 2 /Cu 39 S 28 exhibits a high current output of 500 mA cm -2 at a low overpotential of 370 mV and robust stability for 60 h at 100 mA cm -2 , surpassing the values of most previously reported Cu-based catalysts. Furthermore, a two-electrode electrolyzer made by pairing the prepared catalyst with commercial Pt/C requires a low cell voltage of 1.75 V at 100 mA cm -2 and is retained over 80 h. Key to its excellent performance is the synergism between intertwined FeS 2 and Cu 39 S 28 domains, enriched by the deliberate introduction of sulfur vacancies, thus optimizing the electronic structure and causing the proliferation of catalytic active sites. This work presents a potent Cu-based electrocatalyst and emphasizes the leveraging of non-precious metals for efficient water oxidation.

A high-performance and reusable nonnoble metal catalyst for catalyzing sodium borohydride (NaBH 4 ) hydrolysis to generate H 2 is heralded as a nuclear material for the fast-growing hydrogen economy. Boron vacancy serves as a flexible defect site that can effectively regulate the catalytic hydrolysis performance. Herein, we construct a uniformly dispersed and boron vacancy-rich nonnoble metal Co 2 B-Fe 2 B catalyst via the hard template method. The optimized Co 2 B-Fe 2 B exhibits superior performance toward NaBH 4 hydrolysis, with a high hydrogen generation rate (5315.8 mL min -1 g catalyst -1 ), relatively low activation energy (35.4 kJ mol -1 ), and remarkable cycling stability, outperforming the majority of reported catalysts. Studies have shown that electron transfer from Fe 2 B to Co 2 B, as well as abundant boron defects, can effectively modulate the charge carrier concentration of Co 2 B-Fe 2 B catalysts. Density functional theory calculations confirm that the outer electron cloud density of Co 2 B is higher than that of Fe 2 B, among which Co 2 B with high electron cloud density can selectively adsorb BH 4 - ions, while the electron-deficient Fe 2 B is favorable for capturing H 2 O molecules, therefore synergistically promoting the catalytic NaBH 4 hydrolysis to produce H 2 .

Designing multi-channel mesoporous structure and introducing oxygen vacancies to synergistically enhance oxygen reduction reaction (ORR) activity is crucial for the practical application of zinc-air batteries (ZABs) in the field of energy storage and conversion. Herein, a novel multi-channel mesoporous Bi-Fe 2 O 3 microsphere with abundant oxygen vacancies supported on nitrogen-doped carbon (denoted as Bi-Fe 2 O 3 @NC) is constructed and the designated catalyst demonstrates a higher half-wave potential (0.88 V), large limiting current density (5.8 mA cm -2 @0.4 V), and superior stability. Besides, the aqueous ZAB utilizing Bi-Fe 2 O 3 @NC cathode achieves a high power density of 198.6 mW cm -2 and maintains exceptional stability for 459 h at 5 mA cm -2 , superior to most previously reported catalysts. Furthermore, a solid-state ZAB assembled with Bi-Fe 2 O 3 @NC shows a power density of 55.9 mW cm -2 , highlighting its potential for flexible ZAB applications. The prominent ORR performance of Bi-Fe 2 O 3 @NC can be ascribed to its unique multi-channel mesoporous structure and abundant oxygen vacancies, which increase the exposure of active sites and facilitate efficient electron/mass transport. This work provides valuable insights for the rational design of advanced ORR catalysts for the practical requirements of aqueous/flexible ZABs in energy storage and conversion., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Developing efficient electrocatalysts toward hydrogen oxidation and evolution reactions (HER/HOR) in alkaline electrolytes is essential for realizing renewable hydrogen technologies. Herein, we demonstrate that the introduction of dual-active species such as Mo and P (Pt/Mo,P@NC) can effectively regulate the surface electronic structure of platinum (Pt) and significantly improve the HOR/HER performance. The optimized Pt/Mo,P@NC exhibits remarkable catalytic activity, achieving a normalized exchange current density of 2.89 mA cm -2 and a mass activity of 2.3 mA μg Pt -1 , which are approximately 2.2 and 13.5 times higher than those of the state-of-the-art Pt/C catalyst, respectively. Moreover, it performs an impressive HER performance with an overpotential of 23.4 mV at 10 mA cm -2 , which is lower than most documented alkaline electrocatalysts. Experimental results reveal that the modifying effect of Mo and P optimizes the adsorption of H and OH on Pt/Mo,P@NC, resulting in an outstanding catalytic performance. This work has significant theoretical and practical significance for developing a novel and highly efficient catalyst for bifunctional hydrogen electrocatalysis.

Heteroatom-doped metal-free carbon catalysts for oxygen reduction reactions have gained significant attention because of their unusual activity and economic cost. Here, a novel N/P co-doped porous carbon catalyst (NPPC) with a high surface area for oxygen reduction reaction (ORR) is constructed by a facile high-temperature calcination method employing ZIF-8 as the precursor and red phosphorus as the phosphorus source. In particular, ZIF-8 is firstly calcined to obtain N-doped carbon (NC) followed by further calcination with red phosphorus to obtain NPPC. Ultraviolet photoelectron spectroscopy (UPS) analysis shows that the ultra-low amount of P doping could significantly decrease the work function from 4.32 to 3.86 eV. The resultant catalyst exhibits a promising electrocatalytic activity with a half-wave potential (E 1/2 ) of 0.87 V and a limiting current density (J L ) of 5.15 mA cm -2 . Besides, it also shows improved catalytic efficiency and excellent durability with a negligible decay of J L after 2000 CV cycles. Moreover, aqueous and solid-state flexible zinc-air batteries (ZAB) using the catalyst show a promising application potential. This work provides new insight into developing P/N-doped metal-free carbon ORR catalysts., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Rational designing of a high-efficiency and viable electrocatalyst is essential to conquering the bottleneck of sluggish alkaline hydrogen oxidation/evolution reactions (HOR/HER) kinetics. Herein, a MOF-engaged strategy for constructing Pt-free catalyst with Ru clusters anchored on porous Cu-Cu2O@C support (Ru/Cu-Cu2O@C) is proposed. The designed Ru/Cu-Cu2O@C exhibits superior HOR performance with the mass activity of 2.7 mA μg-1Ru at 50 mV, which is about 24 times higher than state-of-the-art Pt/C (0.11 mA  μg-1Pt). Significantly, Ru/Cu-Cu2O@C also displays an impressive HER performance by generating 26 mV@10 mA cm-2, outperforming majority of documented Ru-based electrocatalysts. Systematic characterization and density functional theory (DFT) calculations reveal that efficient electron transfer between Ru and Cu species results in an attenuated hydrogen binding energy (HBE) of Ru and an enhanced hydroxyl binding energy (OHBE) of Cu2O, together with an optimized H2O adsorption energy with Cu2O as H2O* capturing site, which jointly facilitate HOR/HER kinetics., (© 2023 Wiley-VCH GmbH.)

Developing high-activity, long-durability, and noble metal-free oxygen evolution (OER) and hydrogen evolution (HER) cocatalysts are the bottlenecks for efficient overall water splitting (OWS). Here, novel cobalt vanadium oxides doped by nitrogen were synthesized by nitriding Co 2 V 2 O 7 @NF precursor at 300-450 °C for OER and HER reactions. N-Co 2 V 2 O 7 @NF (350 °C) and N-Co 2 VO 4 /VO 2 @NF (400 °C) show remarkable OER and HER performance with overpotentials of 310 mV and 224 mV at high current density (100 mA cm -2 ). Besides, they also revealed long-term solid stability even after 170 h and 700 h of continuous performance. Furthermore, the N-Co 2 V 2 O 7 @NF (+) ||N-Co 2 VO 4 /VO 2 @NF (-) OWS device possesses a cell voltage of 1.93 V at 500 mA cm -2 better than RuO 2 @NF (+) ||Pt/C@NF (-) (2.02 V) and can operate for 60 h with almost no degradation. This extraordinary performance can be attributed to the nanosheet structure, which can maximize the exposure of active sites and accelerate the mass transfer. Moreover, density functional theory (DFT) calculations suggest that N-doping can fine-tune the d-band center and band gap to facilitate intermediate adsorption and electron motion. The method presented here can be applied in other novel N-doped electrocatalysts for the energy field., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Developing a highly efficient bifunctional catalyst for hydrolysis of metal hydrides and spontaneous hydrogen evolution reaction (HER) is essential for substituting conventional fuels for H2 production. Herein, a sheet-like Ru clusters modified Co3B-Co(OH)2 supported on nickel foam (Ru/Co3B-Co(OH)2@NF) is constructed by electroless deposition, calcination and chemical reduction. The catalyst exhibits an excellent H2 generation activity with a rate of 4989 mL min-1 [[EQUATION]] and good reusability, superior to most previously reported catalysts. Besides, Ru/Co3B-Co(OH)2@NF displays a prominent hydrogen evolution reaction catalytic capability with a low overpotential of 153.0 mV at 100 mA cm-2 (50.5 mV at 10mA cm-2), a small Tafel slope of 40.0 mV dec-1 and long-term stability (100 h@10 mA cm-2) in 1.0 M KOH. The excellent catalytic H2 generation capacity benefits from the rapid charge transfer promoted by metallic Co3B, the synergistically catalytic effect between Co3B-Co(OH)2 and Ru clusters, and the unique composite structure favorable for solute transport and gas emission., (© 2022 Wiley-VCH GmbH.)

Metal-organic frameworks (MOFs) have been considered as potential oxygen evolution reaction (OER) electrocatalysts owning to their ultra-thin structure, adjustable composition, high surface area, and high porosity. Here, we designed and fabricated a vanadium-doped nickel organic framework (V 1-x -Ni x MOF) system by using a facile two-step solvothermal method on nickel foam (NF). The doping of vanadium remarkably elevates the OER activity of V 1-x -Ni x MOF, thus demonstrating better performance than the corresponding single metallic Ni-MOF, NiV-MOF and RuO 2 catalysts at high current density (>400 mA cm -2 ). V 0.09 -Ni 0.91 MOF/NF provides a low overpotential of 235 mV and a small Tafel slope of 30.3 mV dec -1 at a current density of 10 mA cm -2 . More importantly, a water-splitting device assembled with Pt/C/NF and V 0.09 -Ni 0.91 MOF/NF as cathode and anode yielded a cell voltage of 1.96 V@1000 mA cm -2 , thereby outperforming the-state-of-the-art RuO 2 (+) ||Pt/C (-) . Our work sheds new insight on preparing stable, efficient OER electrocatalysts and a promising method for designing various MOF-based materials., (© 2022 Wiley-VCH GmbH.)

Developing cost-effective, highly active, and robust electrocatalysts for oxygen evolution reaction (OER) at high current density is a critical challenge in water electrolysis since the sluggish kinetics of the OER significantly impedes the energy conversion efficiency of overall water splitting. Here, a 1D nanothorn-like Nb-CoSe 2 /CC (CC=carbon cloth) structure was developed as an efficient OER catalyst. The optimized Nb-CoSe 2 /CC catalyst exhibited remarkable OER performance with the low overpotentials of 220 mV at 10 mA cm -2 and 297 mV 200 mA cm -2 and a small Tafel slope (54.1 mV dec -1 ) in 1.0 m KOH electrolyte. More importantly, the Nb-CoSe 2 /CC electrode displayed superior stability after 60 h of continuous operation. In addition, cell voltages of 1.52 and 1.93 V were required to achieve 10 and 500 mA cm -2 for the electrolyzer made of Nb-CoSe 2 /CC (anode) and the Pt/C (cathode). Density functional theory (DFT) calculations combined with experimental results revealed that incorporating niobium into the CoSe 2 could optimize the adsorption free energy of the reaction intermediates and enhance the conductivity to improve the catalytic activity further. Additionally, the super-hydrophilicity of Nb-CoSe 2 /CC resulting from the surface defects increased the surface wettability and facilitated reaction kinetics. These results indicate that Nb-CoSe 2 /CC intrinsically enhances OER performance and possesses potential practical water electrolysis applications., (© 2022 Wiley-VCH GmbH.)

Electrochemical energy conversion and storage through hydrogen has revolutionized sustainable energy systems using fuel cells and electrolyzers. Regrettably, the sluggish alkaline hydrogen oxidation reaction (HOR) hampers advances in fuel cells. Herein, we report a Pt/Ni 3 N-Mo 2 C bifunctional electrocatalyst toward HOR and hydrogen evolution reaction (HER). The Pt/Ni 3 N-Mo 2 C exhibits remarkable HOR/HER performance in alkaline media. The mass activity at 50 mV and exchange current density of HOR are 5.1 and 1.5 times that of commercial Pt/C, respectively. Moreover, it possesses an impressive HER activity with an overpotential of 11 mV @ 10 mA cm -2 , which is lower than that of Pt/C and most reported electrocatalysts under the same conditions. Density functional theory (DFT) calculations combined with experimental results reveal that Pt/Ni 3 N-Mo 2 C not only possesses an optimal balance between hydrogen binding energy (HBE) and OH - adsorption but also facilitates water adsorption and dissociation on the catalyst surface, which contribute to the excellent HOR/HER performance. Thus, this work may guide bifunctional HOR/HER catalyst design in the conversion and transport of energy.

The design and construction of highly efficient and durable non-noble metal bifunctional catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media is essential for developing the hydrogen economy. To achieve this goal, we have developed a bifunctional nanowire-structured FeP-CoP array catalyst on carbon cloth with uniform distribution through in-situ hydrothermal growth and phosphating treatment. The unique nanowire array structure and the strong electronic interaction between FeP and CoP species have been confirmed. Electrochemical studies have found that the designed Fe 0.14 Co 0.86 -P/CC catalyst appears excellent HER (130 mV@10 mA cm -2 )/OER (270 mV@10 mA cm -2 ) activity and stability. Moreover, the bifunctional Fe 0.14 Co 0.86 -P/CC (+/-) catalyst is also used in simulated industrial water splitting system, where the pair catalyst requires about 1.95 and 2.14 V to reach 500 and 1000 mA cm -2 , even superior to the control RuO 2 (+) ||Pt/C (-) catalyst, showing good industrial application prospects. These excellent electrocatalytic properties are attributed to the synergy between FeP and CoP species as well as the unique microstructure, which can accelerate charge transfer, expose more active sites and enhance electrolyte diffusion and gas emissions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Precise identification and in-depth understanding of defects in nanomaterials can aid in rationally modulating defect-induced functionalities. However, few studies have explored vacancy defects in ligand-stabilized metal nanoclusters with well-defined structures, owing to the substantial challenge of synthesizing and isolating such defective metal nanoclusters. Herein, a novel defective copper hydride nanocluster, [Cu 36 H 10 (PET) 24 (PPh 3 ) 6 Cl 2 ] ( Cu36 ; PET: phenylethanethiolate; PPh 3 : triphenylphosphine), is successfully synthesized at the gram scale via a simple one-pot reduction method. Structural analysis reveals that Cu36 is a distorted half cubic nanocluster, evolved from the perfect Nichol's half cube. The two surface copper vacancies in Cu36 are found to be the principal imperfections, which result in some structural adjustments, including copper atom reconstruction near the vacancies as well as ligand modifications (e.g., substitution, migration, and exfoliation). Density functional theory calculations imply that the above-mentioned defects have a considerable influence on the electronic structure and properties. The modeling suggests that the formation of defective Cu36 rather than the perfect half cube is driven by the enlargement of the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital of the nanocluster. The structural evolution induced by the surface copper atom vacancies provides atomically precise insights into the defect-induced readjustment of the local structure and introduces new avenues for understanding the chemistry of defects in nanomaterials.

Designing a bifunctional catalyst for hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) is significant toward developing sustainable hydrogen-electric conversion systems. Herein, a cost-effective bifunctional catalyst, Ru/N-doped Carbon@WO 3 -W 2 C (Ru/NC@WOC), was developed via co-precipitation and polyol reduction. Ru/NC@WOC showed superior HOR/HER activity in alkaline solution in comparison with commercial Pt/C. HOR electrochemical tests showed that the mass activity at 0.05 V (1.96  m A μ g R u - 1 ) and exchange-current density were 7.5 and 1.2 times that of Pt/C. Additionality, Ru/NC@WOC exhibited up 30-fold HOR activity in mass activity compared with benchmark Ru/C. Moreover, it also displayed exceptional electrocatalytic HER with overpotentials of 31 mV at 10 mA cm -2 and 119 mV at 100 mA cm -2 , surpassing Pt/C, benchmark Ru/C, and most of the previously reported electrocatalysts. The outstanding catalytic activity of Ru/NC@WOC probably arises from the synergy between Ru and NC@WOC matrix, suitable hydrogen binding energy, and highly conductive substrate. Thus, this work may pave a new avenue to fabricate low-cost bifunctional HOR/HER catalysts for alkaline fuel cells and water electrolyzer., (© 2021 Wiley-VCH GmbH.)

NaBH 4 is considered the best hydrogen storage material due to its high hydrogen content of 10.6 wt% and good stability. However, NaBH 4 hydrolysis requires an efficient catalyst because of the sluggish reaction kinetics. In this work, we have demonstrated a process of preparing a cobalt phosphide-supported Ru particulate nanocatalyst with abundant phosphorus vacancies for the first time. Electron paramagnetic resonance and transmission electron microscopy revealed that the synthesized Ru 9.8 /r-CoP catalyst has ample phosphorus vacancies, and Ru species are small particles (~2.5 nm) with uniform dispersion, respectively. More importantly, the optimized Ru 9.8 /r-CoP catalyst has the lowest activation energy (45.3 kJ mol -1 ) and exhibits excellent catalytic performance for NaBH 4 hydrolysis with a high hydrogen generation rate 9783.3 mLH 2 min -1 g cat -1 at 25 °C, which is higher than most of the cobalt-based catalysts. Moreover, the Ru 9.8 /r-CoP catalyst also shows good reusability. For example, the catalytic performance only declined by ca. 14% after five cycles. The excellent catalytic performance of Ru 9.8 /r-CoP is attributed to the abundant phosphorus vacancies along with a large specific surface area of r-CoP, which makes the Ru particles smaller and more uniformly dispersed on the surface, thereby exposing more active sites to show improved performance., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Developing a bifunctional catalyst with low cost and high catalytic performance in NaBH 4 hydrolysis for H 2 generation and selective reduction of nitroaromatics will make a significant impact in the field of sustainable energy and water purification. Herein, a low-loading homogeneously dispersed Pd oxide-rich Co 3 O 4 polyhedral catalyst (PdO-Co 3 O 4 ) with concave structure is reported by using a metal-organic framework (MOF)-templated synthesis method. The results show that the PdO-Co 3 O 4 catalyst has an exceptional turnover frequency (3325.6 mol H2  min -1  mol Pd -1 ), low activation energy (43.2 kJ mol -1 ), and reasonable reusability in catalytic H 2 generation from NaBH 4 hydrolysis. Moreover, the optimized catalyst also shows excellent catalytic performance in the NaBH 4 selective reduction of 4-nitrophenol to 4-aminiphenol with a high first-order reaction rate of approximately 1.31 min -1 . These excellent catalytic properties are mainly ascribed to the porous concave structure, monodispersed Pd oxide, as well as the unique synergy between PdO and Co 3 O 4 species, which result in a large specific surface area, high conductivity, and fast solute transport and gas emissions., (© 2020 Wiley-VCH GmbH.)

An industrial electro-catalyst obliges three essential features, such as scalability, generating high current density at low overpotential, and long-term stability. Herein, we tackle those challenges using NiS x -MoO 2 nanosponges on carbon cloth based hydrogen evolution catalyst. The target catalyst was synthesized through a series of simple and scalable methods, including dissolution, reconstruction, and chemical vapor deposition. The optimized NiS x -MoO 2 /CC catalyst exhibits a superior hydrogen evolution catalytic activity far better than commercial Pt/C meanwhile surpasses widely used industrial Raney Ni catalyst by many aspects, namely lower overpotential at 500 mA cm -2 current density and smaller Tafel plot in 30 wt% KOH solution. This excellent electrocatalytic activity is attributed to enhanced mass transfer and faster reaction kinetics due to the unique hierarchical porous structures, as well as the synergistic electron transfer effect between the two components of NiS x and MoO 2 species. This work may provide a new strategy for the design of better hydrogen evolution catalyst for industrial application., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The effect of electrode area, electrolyte concentration, temperature, and light intensity (up to 218 sun) on PV electrolysis of water is studied using a high concentrated triple-junction (3-J) photovoltaic cell (PV) connected directly to an alkaline membrane electrolyzer (EC). For a given current, the voltage requirement to run an electrolyzer increases with a decrease in electrode sizes (4.5, 2.0, 0.5, and 0.25 cm 2 ) due to high current densities. The high current density operation leads to high Ohmic losses, most probably due to the concentration gradient and bubble formation. The EC operating parameters including the electrolyte concentration and temperature reduce the voltage requirement by improving the thermodynamics, kinetics, and transport properties of the overall electrolysis process. For a direct PV-EC coupling, the maximum power point of PV ( P max ) is matched using EC I - V (current-voltage) curves measured for different electrode sizes. A shift in the EC I - V curves toward open-circuit voltage ( V oc ) reduces the P op (operating power) to hydrogen efficiencies due to the increased voltage losses above the equilibrium water-splitting potential. The solar-to-hydrogen (STH) efficiencies remained comparable (∼16%) for all electrode sizes when the operating current ( I op ) was similar to the short-circuit current ( I sc ) irrespective of the operating voltage ( V op ), electrolyzer temperature, and electrolyte concentration., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

We have investigated a Z-scheme based on a ZnO/Pt/CdZnS photocatalyst, active in the presence of a complex medium composed of acetic acid and benzyl alcohol, the effects of which on the catalyst stability and performance are studied. Transmission electron microscopy images showed uniformly dispersed sub-nanometer Pt particles. Inductively coupled plasma and X-ray photoelectron spectroscopy analyses suggested that Pt is sandwiched between ZnO and CdZnS. An apparent quantum yield (AQY) of 34% was obtained over the [ZnO] 4 /1 wt %Pt/CdZnS system at 360 nm, 2.5-fold higher than that of 1%Pt/CdZnS (14%). Furthermore, an AQY of 16% was observed using [ZnO] 4 /1 wt %Pt/CdZnS, which was comparable to that of 1 wt %Pt/CdZnS (10%) at 460 nm. On the basis of these results, we proposed a charge transfer mechanism, which was confirmed through femtosecond transient absorption spectroscopy. Finally, we identified the two main factors that affected the stability of the catalyst, which were the sacrificial reagent and the acidic pH., Competing Interests: The authors declare no competing financial interest.

Highly transparent and UV-resistant superhydrophobic arrays of SiO2-coated ZnO nanorods are prepared in a sequence of low-temperature (<150 °C) steps on both glass and thin sheets of PET (2 × 2 in.(2)), and the superhydrophobic nanocomposite is shown to have minimal impact on solar cell device performance under AM1.5G illumination. Flexible plastics can serve as front cell and backing materials in the manufacture of flexible displays and solar cells.

We explored biexciton generation via carrier multiplication (or multiple-exciton generation) by high-energy photons and by multiple-photon absorption in Ag2S quantum dots (QDs) using femtosecond broad-band transient absorption spectroscopy. Irrespective of the size of the QDs and how the multiple excitons are generated in the Ag2S QDs, two distinct characteristic time constants of 9.6-10.2 and 135-175 ps are obtained for the nonradiative Auger recombination of the multiple excitons, indicating the existence of two binding excitons, namely, tightly bound and weakly bound excitons. More importantly, the lifetimes of multiple excitons in Ag2S QDs were about 1 and 2 orders of magnitude longer than those of comparable size PbS QDs and single-walled carbon nanotubes, respectively. This result is significant because it suggests that by utilizing an appropriate electron acceptor, there is a higher possibility to extract multiple electron-hole pairs in Ag2S QDs, which should improve the performance of QD-based solar cell devices.

Pramanicin (PMC) is an antifungal agent that was previously demonstrated to exhibit antiangiogenic and anticancer properties in a few in vitro studies. We initially screened a number of PMC analogs for their cytotoxic effects on HCT116 human colon cancer cells. PMC-A, the analog with the most potent antiproliferative effect was chosen to further interrogate the underlying mechanism of action. PMC-A led to apoptosis through activation of caspase-9 and -3. The apoptotic nature of cell death was confirmed by abrogation of cell death with pretreatment with specific caspase inhibitors. Stress-related MAPKs JNK and p38 were both activated concomittantly with the intrinsic apoptotic pathway. Moreover, pharmacological inhibition of p38 proved to attenuate the cell death induction while pretreatment with JNK inhibitor did not exhibit a protective effect. Resistance of Bax -/- cells and the protective nature of caspase-9 inhibition indicate that mitochondria play a central role in PMC-A induced apoptosis. Early post-exposure elevation of cellular Bim and Bax was followed by a marginal Bcl-2 depletion and Bid cleavage. Further analysis revealed that Bcl-2 downregulation occurs at the mRNA level and is critical to mediate PMC-A induced apoptosis, as ectopic Bcl-2 expression substantially spared the cells from death. Conversely, forced expression of Bim proved to significantly increase cell death. In addition, analyses of p53-/- cells demonstrated that Bcl-2/Bim/Bax modulation and MAPK activations take place independently of p53 expression. Taken together, p53-independent transcriptional Bcl-2 downregulation and p38 signaling appear to be the key modulatory events in PMC-A induced apoptosis.

Efficient oxygen supply is a continuing challenge for the fabrication of successful tissue engineered constructs with clinical relevance. In an effort to enhance oxygen delivery we report the feasibility of using fluorinated zeolite particles embedded in three-dimensional (3-D) polyurethane scaffolds as novel oxygen vectors. First, 1H,1H,2H,2H-perfluorodecyltriethoxysilane was successfully coupled to zeolite framework particles to examine the dose-dependent dissolved oxygen concentration. Following this, the fluorinated-zeolite (FZ) particles were embedded in 3-D tissue engineering polyurethane scaffolds. Our data demonstrates an even distribution of FZ particles in the 3-D scaffolds without affecting the scaffold porosity or pore size. Human coronary artery smooth muscle cell (HCASMC) proliferation on FZ-containing polyurethane (PCU-FZ) scaffolds was significantly greater than on control scaffolds (P=0.05). Remarkably, cell infiltration depths on the PCU-FZ scaffolds was double that on PCU control scaffolds. Taken together, our data suggest the potential of PCU-FZ scaffolds for tissue engineering with enhanced oxygen delivery to cells., (Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Visible light transparent, UV-shielding and superhydrophobic nanostructured coatings have been successfully fabricated through a facile layer-by-layer deposition of TiO(2) and SiO(2) nanoparticles. The coatings are composed of an underlying UV-shielding TiO(2) layer and a top fully covered protective SiO(2) layer. The resulting coatings can block 100% of UVB and UVC and almost 85% of UVA. The fabricated surfaces have contact angles exceeding 165° after coating with organic PTES (1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane) molecules. The transparent superhydrophobic surfaces exhibit extremely strong UV stability. All coatings retain the initial UV-shielding and superhydrophobic properties even after exposure to 275 nm UV light with a light intensity of 75 mW cm(-2) for 12 h.

An innovative route to prepare highly-ordered and dimensionally controlled TiO2 nanotubes has been proposed using a mild sonication method. The nanotube arrays were prepared by the anodization of titanium in an electrolyte containing 3% NH4F and 5% H2O in glycerol. It is demonstrated that the TiO2 nanostructures has two layers: the top layer is TiO2 nanowire and underneath is well-ordered TiO2 nanotubes. The top layer can easily fall off and form nanowires bundles by implementing a mild sonication after a short annealing time. We found that the dimensions of the TiO2 nanotubes were only dependent on the anodizing condition. The proposed technique may be extended to fabricate reproducible well-ordered TiO2 nanotubes with large area on other metals.

A one-step method for the fabrication of Fe-C-N-codoped TiO2 nanotubes by electrochemical anodization is reported. The proposed method is both simple and efficient. The prepared samples were annealed at 550 degrees C for 3 h. The resulting nanotubes were characterized by SEM, XRD, XPS, EDX and UV-vis spectrophotometer. The results showed that the average tube diameter of the nanotubes was 70 nm and wall thickness was 20 nm and the average tube length was 2.4 microm. The doped TiO2 nanotubes exhibited strong absorption in the visible-light region. The maximum photocurrent efficiency measured under solar simulator was 2.7%.