Electrochemical oxygen reduction reaction via the two-electron pathway(2e-ORR)is becoming a promising and sustainable approach to producing hydrogen peroxide(H_(2)O2)without significant carbon footprints.To achieve be...Electrochemical oxygen reduction reaction via the two-electron pathway(2e-ORR)is becoming a promising and sustainable approach to producing hydrogen peroxide(H_(2)O2)without significant carbon footprints.To achieve better performance,most of the recent progress and investigations have focused on developing novel carbon-based electrocatalysts.Nevertheless,the sophisticated preparations,decreased selectivity and undefined active sites of carbon-based catalysts have been generally acknowledged and criticized.To this end,transition metal oxides and chalcogenides have increasingly emerged for 2e-ORR,due to their catalytic stability and tunable microstructure.Here,the development of metal oxides and chalcogenides for O2-to-H_(2)O2 conversion is prospectively reviewed.By summarizing previous theoretical and experimental efforts,their diversity and outstanding catalytic activity are firstly provided.Meanwhile,the topological and chemical factors influencing 2e-ORR selectivity of the metal oxides/chalcogenides are systematically elucidated,including morphology,phase structures,doping and defects engineering.Thus,emphasizing the influence on the binding of ORR intermediates,the active sites and the underlying mechanism is highlighted.Finally,future opportunities and challenges in designing metal oxides/chalcogenides-based catalysts for H_(2)O2 electro-synthesis are outlined.The present review provides insights and fundamentals of metal oxides/chalcogenides as 2e-ORR catalysts,promoting their practical application in the energy-related industry.展开更多
Zinc-air batteries(ZnABs) with high theoretical capacity and environmental benignity are the most promising candidates for next-generation electronics. However, their large-scale applications are greatly hindered due ...Zinc-air batteries(ZnABs) with high theoretical capacity and environmental benignity are the most promising candidates for next-generation electronics. However, their large-scale applications are greatly hindered due to the lack of high-efficient and cost-effective electrocatalysts. Transition metal phosphides(TMPs) have been reported as promising electrocatalysts. Notably,(Ni_(1-x)Cr_(x))_(2) P(0≤x≤0.15) is an unstable electrocatalyst, which undergoes in-situ electrochemical oxidation during the initial oxygen evolution reaction(OER) and even in the activation cycles, and is eventually converted to Cr-NiOOH serving as the actual OER active sites with high efficiency. Density functional theory(DFT) simulations and experimental results elucidate that the OER performance could be significantly promoted by the synergistic effect of surface engineering and electronic modulations by Cr doping and in-situ phase transformation. The constructed rechargeable ZnABs could stably cycle for more than 208 h at 5 m A cm^(-2), while the voltage degradation is negligible. Furthermore, the developed catalytic materials could be assembled into flexible and all-solid-state Zn ABs to power wearable electronics with high performance.展开更多
文摘Electrochemical oxygen reduction reaction via the two-electron pathway(2e-ORR)is becoming a promising and sustainable approach to producing hydrogen peroxide(H_(2)O2)without significant carbon footprints.To achieve better performance,most of the recent progress and investigations have focused on developing novel carbon-based electrocatalysts.Nevertheless,the sophisticated preparations,decreased selectivity and undefined active sites of carbon-based catalysts have been generally acknowledged and criticized.To this end,transition metal oxides and chalcogenides have increasingly emerged for 2e-ORR,due to their catalytic stability and tunable microstructure.Here,the development of metal oxides and chalcogenides for O2-to-H_(2)O2 conversion is prospectively reviewed.By summarizing previous theoretical and experimental efforts,their diversity and outstanding catalytic activity are firstly provided.Meanwhile,the topological and chemical factors influencing 2e-ORR selectivity of the metal oxides/chalcogenides are systematically elucidated,including morphology,phase structures,doping and defects engineering.Thus,emphasizing the influence on the binding of ORR intermediates,the active sites and the underlying mechanism is highlighted.Finally,future opportunities and challenges in designing metal oxides/chalcogenides-based catalysts for H_(2)O2 electro-synthesis are outlined.The present review provides insights and fundamentals of metal oxides/chalcogenides as 2e-ORR catalysts,promoting their practical application in the energy-related industry.
基金supported by the National Natural Science Foundation of China (21603019 and 201503025)the National Key Research and Development Program of China (2016YFE0125900)the program for the Hundred Talents Program of Chongqing University。
文摘Zinc-air batteries(ZnABs) with high theoretical capacity and environmental benignity are the most promising candidates for next-generation electronics. However, their large-scale applications are greatly hindered due to the lack of high-efficient and cost-effective electrocatalysts. Transition metal phosphides(TMPs) have been reported as promising electrocatalysts. Notably,(Ni_(1-x)Cr_(x))_(2) P(0≤x≤0.15) is an unstable electrocatalyst, which undergoes in-situ electrochemical oxidation during the initial oxygen evolution reaction(OER) and even in the activation cycles, and is eventually converted to Cr-NiOOH serving as the actual OER active sites with high efficiency. Density functional theory(DFT) simulations and experimental results elucidate that the OER performance could be significantly promoted by the synergistic effect of surface engineering and electronic modulations by Cr doping and in-situ phase transformation. The constructed rechargeable ZnABs could stably cycle for more than 208 h at 5 m A cm^(-2), while the voltage degradation is negligible. Furthermore, the developed catalytic materials could be assembled into flexible and all-solid-state Zn ABs to power wearable electronics with high performance.
