Cu^+-incorporated TiO_2 overlayer on Cu_2O nanowire photocathodes for enhanced photoelectrochemical conversion of CO_2 to methanol

作     者：Kangha Lee Seokwon Lee Hyunjin Cho Sunil Jeong Whi Dong Kim Sooho Lee Doh C.Lee 

作者机构：Department of Chemical and Biomolecular Engineering(BK21+program)KAIST Institute for the NanocenturyKorea Advanced Institute of Science and Technology(KAIST) 

出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)

年 卷 期：2018年第27卷第1期

页      面：264-270页

核心收录：

学科分类：0820[工学-石油与天然气工程] 081702[工学-化学工艺] 0808[工学-电气工程] 081704[工学-应用化学] 0817[工学-化学工程与技术] 08[工学] 0807[工学-动力工程及工程热物理] 0827[工学-核科学与技术] 0703[理学-化学] 

基　　金：supported by the National Research Foundation (NRF) grants funded by the Korean government (no.NRF-20110030256, NRF-2017R1A2B2011066 and NRF-2016M3A7B4910618) funded by the Saudi Aramco-KAIST CO2 Management Center 

主　　题：Photoelectrochemical CO2 reductionMethanol generation Copper oxide Titanium dioxide Cu+ catalyst 

摘      要：In this paper, we report photoelectrochemical（PEC） conversion of carbon dioxide（CO_2） using photocathodes based on Cu_2O nanowires（NWs） overcoated with Cu~＋-incorporated crystalline TiO_2（TiO_2–Cu~＋ ）shell. Cu_2O NW photocathodes show remanent photocurrent of 5.3% after 30 min of PEC reduction of CO_*** coating Cu_2O with TiO_2–Cu~＋ overlayer, the remanent photocurrent is 27.6%, which is an increase by5.2 fold. The charge transfer resistance of Cu_2O/TiO_2–Cu~＋ is 0.423 k/cm2, whereas Cu_2O photocathode shows resistivity of 0.781 k/cm2 under irradiation. Mott–Schottky analysis reveals that Cu~＋ species embedded in TiO_2 layer is responsible for enhanced adsorption of CO_2 on TiO_2 surface, as evidenced by the decrease of capacitance in the Helmholtz layer. On account of these electrochemical and electronic effects by the Cu~＋ species, the Faradaic efficiency（FE） of photocathodes reaches as high as 56.5% when TiO_2–Cu~＋ is added to Cu_2O, showing drastic increase from 23.6% by bare Cu_2O photocathodes.