Separation of oxidation and reduction sites on Zn0.3Cd0.7S for efficient photocatalytic hydrogen production

Separation of redox sites is one of the methods to control the directional separation of photogenerated charges and improve photocatalytic activity. Herein, we constructed a novel system that integrating Ti3C2Tx, Zn0.3Cd0.7S (ZCS) and CoP for efficient photocatalytic hydrogen production. The hydrogen production rate of this system can reach 9.67 mmol g−1 h−1, with long-term stability of 20 h. The results show that Ti3C2Tx has smallest (work function (Wf)) compared with ZCS and CoP, resulting in the formation of ohmic contact between Ti3C2Tx and ZCS, and Schottky contact between CoP and ZCS. The presence of the Schottky barrier and the built-in electric field leads to a continuous transfer and accumulation of electrons from ZCS to CoP, which then undergoes a reduction reaction with hydrogen ions adsorbed on the surface to generate hydrogen gas and desorb it. The holes in Ti3C2Tx are consumed by sacrificial reagents, allowing effective separation oxidation and reduction sites. Interestingly, there is almost no potential barrier in the Ohmic contact, which still drives the charge transfer from Ti3C2Tx to ZCS. This article presents a new method to regulate charge mobility, namely redox site separation, which helps to achieve better photocatalytic activity.