Tetrafunctional Cu2S thin layers on Cu2O nanowires for efficient photoelectrochemical water splitting  

作　　者：Zhenzhen Li Zhonghai Zhang 

机构地区：[1]School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200241, China

出　　处：《Nano Research》2018年第3期1530-1540,共11页纳米研究（英文版）

基　　金：Z.H.Z. thanks to the support from ＂Yingcai＂ program of ECNU and the National Natural Science Foundation of China （NSFC） （No. 21405046）.

摘　　要：Photoelectrochemical （PEC） water splitting by photocathodes based on p-type semiconductors is a promising process for direct and efficient hydrogen generation. The identification of ideal photocathode materials with a high photoconversion efficiency and long-term stability is still a significant challenge. Herein, we propose a new photocathode consisting of Cu2S-coated Cu2O nanowires （NWs） supported on a three-dimensional porous copper foam. The Cu2S thin layer is generated in situ on the surface of the Cu2O NWs and has four functions： （1） sensitizer, with a band gap of 1.2 eV, for extending the range of optical absorption into the near-infrared region; （2） electron trapper, with appropriate energy level alignment to Cu2O, for achieving effective electron transfer and trapping; （3） electrocatalyst, with excellent electrocatalytic activity for the hydrogen evolution reaction; and （4） protector, preventing direct contact between Cu2O and the electrolyte in order to significantly increase the stability. A photocathode based on the tetrafunctional Cu2S-coated Cu2O NWs exhibits significantly enhanced PEC performance and remarkably improved long-term stability under illumination. The present strategy, based on the in situ generation of multifunctional layers, opens a new avenue for the rational design of photocathodes for PEC water reduction.Photoelectrochemical （PEC） water splitting by photocathodes based on p-type semiconductors is a promising process for direct and efficient hydrogen generation. The identification of ideal photocathode materials with a high photoconversion efficiency and long-term stability is still a significant challenge. Herein, we propose a new photocathode consisting of Cu2S-coated Cu2O nanowires （NWs） supported on a three-dimensional porous copper foam. The Cu2S thin layer is generated in situ on the surface of the Cu2O NWs and has four functions： （1） sensitizer, with a band gap of 1.2 eV, for extending the range of optical absorption into the near-infrared region; （2） electron trapper, with appropriate energy level alignment to Cu2O, for achieving effective electron transfer and trapping; （3） electrocatalyst, with excellent electrocatalytic activity for the hydrogen evolution reaction; and （4） protector, preventing direct contact between Cu2O and the electrolyte in order to significantly increase the stability. A photocathode based on the tetrafunctional Cu2S-coated Cu2O NWs exhibits significantly enhanced PEC performance and remarkably improved long-term stability under illumination. The present strategy, based on the in situ generation of multifunctional layers, opens a new avenue for the rational design of photocathodes for PEC water reduction.

关 键 词：cuprous oxide cuprous sulfide NANOWIRE PHOTOCATHODE water reduction 

分 类 号：O614.121[理学—无机化学] TV86[理学—化学]