Phase transformation of bimetal zinc nickel oxide to oxysulfide photocatalyst with its exceptional performance to evolve hydrogen

This report investigated the effect of sulfur content on phase transformation of bimetal zinc nickel oxide to oxysulfide, which simultaneously affected the performance on photocatalytic hydrogen production. Different amounts of sulfur precursor (0, 0.25, 0.5, 0.75 and 1 mmol) were added to the bimetal oxide during the hydrothermal preparation process. The as-prepared catalysts were carefully characterized with necessary analyses such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–vis spectrophotometer, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, Brunauer-Emmett-Teller (BET) and transient photo current analyses. The sulfur content significantly affected not only the morphology and phase structure but also greatly improved the hydrogen production rate. The maximum hydrogen production rate of 3375 μmol/h corresponding to apparent quantum yield of 28.5 % was achieved by using S-0.75 catalyst, which was 333-fold as compared to that with the catalyst before phase transformation. Herein, we demonstrated the importance of our design to transform the oxide to oxysulfide phase with exceptional performance of hydrogen evolution.