Improved Hydrogen Production Rate of a Nickel-Doped Zinc Indium Oxysulfide Visible-Light Catalyst: Comparative Study of Stoichiometric and Nonstoichiometric Compounds

Photocatalytic hydrogen production has been considered as one of the effective methods to produce hydrogen as a green energy carrier in the future. This report systematically investigates the effect of nickel doping on the crystal structure, optical properties, and photocatalytic hydrogen production rate of the ZnInOS/In(OH)(3) nanocomposite (denoted as ZI-50). It is found that nickel doping could transform the phase of ZI-50 from two phases of ZnInOS and In(OH)(3) into a single phase with a ZnIn2S4 spinel structure. More importantly, all Ni-doped ZI-50 catalysts are nonstoichiometric and highly defective with a Zn(Zn,Ni,In)(2)(O,S)(4-x) spinel structure. 10% nickel precursor-doped ZI-50 as the best catalyst can achieve the highest hydrogen evolution reaction rate of 1700 mu mol/g.h, which is much higher than those of Ni-free ZI-50 (340 mu mol/g.h) and stoichiometric ZnIn2S4 (110 mu mol/g.h). A kinetic mechanism for enhancing photocatalytic hydrogen evolution based upon the cationic antisite defects and anionic oxygen vacancy was proposed and explained.

Automated summary

This study systematically investigates the effect of nickel doping on the crystal structure and photocatalytic hydrogen production of ZnInOS/In(OH)(3) nanocomposite. It is found that nickel doping can transform the crystal structure and enhance the hydrogen production rate. The 10% nickel-doped ZI-50 catalyst shows the highest hydrogen evolution reaction rate.