Modification CuInS2 nanosheet arrays with Fe2V4O13 nanoparticles to construct a photocathode simultaneously with type II heterojunction and p-n junction for enhanced photoelectrochemical water splitting hydrogen evolution

Rational design and construction of semiconductor heterojunction photoelectrode can effectively improve photoelectrochemical (PEC) water splitting for hydrogen evolution . In this study, for the first time, a novel n-type Fe 2 V 4 O 13 (FVO) nanoparticle-modified p-type CuInS 2 (CIS) nanosheet arrays (NSAs) photocathode is designed and constructed for hydrogen evolution through PEC cell . The CIS/FVO NSAs photocathode simultaneously with type II heterojunction and p-n junction was constructed by growing FVO nanoparticles (NPs) on CIS NSAs through a facile successive ionic layer adsorption and reaction (SILAR) as well as annealing method. The designed and constructed CIS/FVO NSAs photocathode exhibited drastically improved PEC water splitting for hydrogen evolution and generated a photocurrent of −4.8 mA/cm 2 , 9.5 times that of pristine CIS NSAs photocathode at −1.0 V vs. Ag/AgCl. UV–vis absorption spectrum tests demonstrated the outstanding light absorption of CIS/FVO NSAs within the wavelength of 300–800 nm. Electrochemical impedance and photoluminescence measurements evidenced the effective separation of the carriers within the CIS/FVO NSAs. Mott-Schottky tests confirmed the establishment of type II heterojunction between the interface of p-type CIS and n-type FVO. The experimental tests revealed that the enhanced PEC water splitting performance of the CIS/FVO NSAs photocathode is attributed to the outstanding light absorption and the effective charge carrier separation achieved by type II heterojunction and p-n junction. This work provides a new strategy to design and construct CIS-based photocathode for highly efficient PEC water splitting hydrogen evolution.