Bias distribution and regulation in photoelectrochemical overall water-splitting cells  

作　　者：Kun Dang Siqin Liu Lei Wu Daojian Tang Jing Xue Jiaming 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：《National Science Review》2024年第4期135-144,共10页国家科学评论（英文版）

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

摘　　要：The water oxidation half-reaction at anodes is always considered the rate-limiting step of overall water splitting(OWS),but the actual bias distribution between photoanodes and cathodes of photoelectrochemical(PEC)OWS cells has not been investigated systematically.In this work,we find that,for PEC cells consisting of photoanodes(nickel-modified n-Si[Ni/n-Si]andα-Fe_(2)O_(3))with low photovoltage(V_(ph)<1 V),a large portion of applied bias is exerted on the Pt cathode for satisfying the hydrogen evolution thermodynamics,showing a thermodynamics-controlled characteristic.In contrast,for photoanodes(TiO2 and BiVO4)with V_(ph)>1 V,the bias required for cathode activation can be significantly reduced,exhibiting a kinetics-controlled characteristic.Further investigations show that the bias distribution can be regulated by tuning the electrolyte pH and using alternative half-reaction couplings.Accordingly,a volcano plot is presented for the rational design of the overall reactions and unbiased PEC cells.Motivated by this,an unbiased PEC cell consisting of a simple Ni/n-Si photoanode and Pt cathode is assembled,delivering a photocurrent density of 5.3±0.2 mA cm^(−2).

关 键 词：PHOTOELECTROCHEMISTRY overall reaction cell bias distribution PHOTOANODE water splitting 

分 类 号：TM91[电气工程—电力电子与电力传动] O646[理学—物理化学]