Construction of CuInS2/Ag sensitized ZnO nanowire arrays for efficient hydrogen generation

Abstract

CuInS₂ has attracted much attention for application in solar energy due to its small and tunable band gap. It has demonstrated high photoelectric conversion efficiency as a photocathode for solar cells, and it is also suitable for hydrogen generation under visible light (E_CBM = −0.44 eV, E_VBM = 1.06 eV, vs. NHE). However, there are rare reports of water splitting based on CuInS₂. In this work, a simple solution method was designed to decorate a ZnO nanowire (NW) array grown on a FTO substrate with Ag and CuInS₂ nanoparticles (NPs). The photoelectrochemical (PEC) activities and hydrogen generation performances were studied. Compared with a bare ZnO NW array, a steady photocurrent increases 100-fold for the ZnO/Ag/CIS system (ZAC) under visible illumination. The solar-to-chemical energy conversion efficiency reaches up to 0.05% with excellent stability. It is expected that this conversion efficiency may be further enhanced several times by increasing the length of the ZnO NWs and controlling the distribution of CuInS₂ and Ag NPs on the ZnO NWs.