Oxygen vacancies(Vo)in electrocatalysts are closely correlated with the hydrogen evo-lution reaction(HER)activity.The role of vacancy defects and the effect of their concentration,how-ever,yet remains unclear.Herein,Bi2O3,an unfavorable electrocata-lyst for the HER due to a less than ideal hydrogen adsorption Gibbs free energy(ΔGH*),is utilized as a perfect model to explore the func-tion of Vo on HER performance.Through a facile plasma irradia-tion strategy,Bi2O3 nanosheets with different Vo concentrations are fabricated to evaluate the influence of defects on the HER process.Unexpectedly,while the generated oxygen vacancies contribute to the enhanced HER performance,higher Vo concentrations beyond a saturation value result in a significant drop in HER activity.By tunning the Vo concentration in the Bi2O3 nanosheets via adjusting the treatment time,the Bi2O3 catalyst with an optimized oxygen vacancy concentration and detectable charge carrier concentration of 1.52 x 1024 cm-3 demonstrates enhanced HER performance with an overpotential of 174.2 mV to reach 10 mA cm-2,a Tafel slope of 80 mV dec-1,and an exchange current density of 316 mA cm-2 in an alkaline solution,which approaches the top-tier activity among Bi-based HER electrocatalysts.Density-functional theory calculations confirm the preferred adsorption of H* onto Bi2O3 as a function of oxygen chemical potential(ΔμO)and oxygen partial potential(PO2)and reveal that high Vo concentrations result in excessive stability of adsorbed hydrogen and hence the inferior HER activity.This study reveals the oxygen vacancy concentration-HER catalytic activity relationship and provides insights into activating catalytically inert materials into highly efficient electrocatalysts.

Ziyang Wu;Ting Liao;Sen Wang;Janith Adikaram Mudiyanselage;Aaron S.Micallef;Wei Li;Anthony P.O'Mullane;Jianping Yang;Wei Luo;Kostya Ostrikov;Yuantong Gu;Ziqi Sun

School of Mechanical,Medical and Process Engineering,Queensland University of Technology,2 George Street,Brisbane,QLD 4000,Australia;Centre for Materials Science,Queensland University of Technology,2 George Street,Brisbane,QLD 4000,Australia;School of Earth and Atmospheric Sciences,Queensland University of Technology,2 George Street,Brisbane,QLD 4000,Australia;School of Chemistry and Physics,Queensland University of Technology,2 George Street,Brisbane,QLD 4000,Australia;Central Analytical Research Facility,Queensland University of Technology,2 George Street,Brisbane,QLD 4000,Australia;State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,College of Materials Science and Engineering,Donghua University,Shanghai 201620,People's Republic of China

纳微快报（英文）

[1]Ziyang Wu;Ting Liao;Sen Wang;Janith Adikaram Mudiyanselage;Aaron S.Micallef;Wei Li;Anthony P.O'Mullane;Jianping Yang;Wei Luo;Kostya Ostrikov;Yuantong Gu;Ziqi Sun-.Conversion of Catalytically Inert 2D Bismuth Oxide Nanosheets for Effective Electrochemical Hydrogen Evolution Reaction Catalysis via Oxygen Vacancy Concentration Modulation)[J].纳微快报（英文）,2022(06):48-64

Catalytically,tunning

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