Boosting multi-hole water oxidation catalysis on hematite photoanodes under low bias  

作　　者：Lei Wu Daojian Tang Jing Xue Shuobo Wang Hongwei Ji Chuncheng Chen Yuchao Zhang Jincai Zhao 

机构地区：[1]Key Laboratory of Photochemistry,CAS Research/Education Center for Excellence in Molecular Sciences,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China Chemistry》2023年第3期896-903,共8页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(22072158);the National Key R&D Program of China(2022YFA1505000,2020YFC1808401);the Strategic Priority Research Program of Chinese Academy of Sciences(XDB36000000);CAS Project for Young Scientists in Basic Research(YSBR-004).

摘　　要：The accumulation of multiple surface holes is considered to be the key to efficient photoelectrochemical(PEC)water oxidation.Previous PEC water oxidation studies commonly apply high potentials(>1.2 VRHE)to achieve this key.But how to complete multi-hole transfer under low bias(<1.2 VRHE)remains unknown.Herein,we find that,on a typical visible-light photoanode,hematite(α-Fe_(2)O_(3)),UV excitation plays a indispensable role in driving multi-hole water oxidation under low bias.Compared with the visible-light excitation,the UV excitation promotes the formation of adjacent surface-trapped holes onα-Fe_(2)O_(3) at 0.9VRHE,thereby increasing the reaction order of surface holes from~1 to~2 and improving the PEC water oxidation activity by one order of magnitude.The UV irradiation reduces the formation probability of self-trapped excitons and results in~3 to 5-fold increase of surface holes.These advantages enable the UV excitation to contribute about 40%to the total photocurrent under 1 solar illumination,even though its energy only occupies 6%of the incident light.This mechanism is also applicable to boost selective two-hole oxidation of thioether at 0.1 VFc/Fc+and nitrite at 0.9 VRHE.

关 键 词：HEMATITE photo(electro)catalysis water oxidation excitation wavelength multi-hole catalysis 

分 类 号：O643.36[理学—物理化学]