Chelation-mediated in-situ formation of ultrathin cobalt(oxy)hydroxides on hematite photoanode towards enhanced photoelectrochemical water oxidation  

作　　者：Zhenzhen Wang Jiayue Rong Jiaqi Lv Ruifeng Chong Ling Zhang Li Wang Zhixian Chang Xiang Wang 

机构地区：[1]Henan Joint International Research Laboratory of Environmental Pollution Control Materials,Henan Provincial Engineering Research Center of Green Anticorrosion Technology for Magnesium Alloys,College of Chemistry and Chemical Engineering,Henan University,Kaifeng 475004,Henan,China [2]Chemical Science Division and Center for Nanophase Materials Sciences,Oak Ridge National Laboratory,Oak Ridge,TN 37831,United States

出　　处：《Journal of Energy Chemistry》2021年第5期152-161,共10页能源化学（英文版）

基　　金：supported by the National Natural Science Foundation of China(51502078);the Major Project of Science and Technology,Education Department of Henan Province(19A150019 and 19A150018);the Science and Technology Research Project of Henan Province(192102310490 and 182102410090);the program for Science&Technology Innovation Team in Universities of Henan Province(19IRTSTHN029);supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Chemical Sciences,Geosciences,and Biosciences Division,Catalysis Science program。

摘　　要：In this work,a facile chelation-mediated route was developed to fabricate ultrathin cobalt(oxy)hydroxides(CoOOH)nanosheets on hematite photoanode(Fe_(2)O_(3)).The route contains two steps of the adsorption of[Co-EDTA]^(2-)species on Fe_(2)O_(3) nanorod array followed by the hydrolysis in alkaline solution.The resulting CoOOH/Fe_(2)O_(3) exhibits a remarkably improved photocurrent density of 2.10 mA cm^(-2) at 1.23 V vs.RHE,which is ca.2.8 times that of bare Fe_(2)O_(3).In addition,a negative shift of onset potential ca.200 mV is achieved.The structural characterizations reveal the chelate EDTA plays important roles that enhance the adsorption of Co species and the formation of contact between CoOOH and Fe_(2)O_(3).(Photo)electrochemical analysis suggests,besides providing active sites for water oxidation,CoOOH at large extent promotes the charge separation and the charge transfer via passivating surface states and suppressing charge recombination.It also found CoOOH possesses some oxygen vacancies,which could act as trapping centers for photogenerated holes and facilitate the charge separation.Intensity modulated photocurrent spectroscopy(IMPS)shows that,under low applied potential the water oxidation mainly occurs on CoOOH,while under high applied potential the water oxidation could occur on both CoOOH and Fe_(2)O_(3).The findings not only provide an efficient strategy for designing ultrathin(oxy)hydroxides on semiconductors for PEC applications but also put forward a new insight on the role of CoOOH during water oxidation.

关 键 词：HEMATITE Cobalt(oxy)hydroxides Photoelectrochemical water oxidation Charge separation 

分 类 号：TQ116.2[化学工程—无机化工] TQ426[一般工业技术—材料科学与工程] TB383.1