Sulfur Vacancy and Ti3C2Tx Cocatalyst Synergistically Boosting Interfacial Charge Transfer in 2D/2D Ti3C2Tx/ZnIn2S4 Heterostructure for Enhanced Photocatalytic Hydrogen Evolution

Constructing an efficient photoelectron transfer channel to promote the charge carrier separation is a great challenge for enhancing photocatalytic hydrogen evolution from water. In this work, an ultrathin 2D/2D Ti3C2Tx/ZnIn2S4 heterostructure is rationally designed by coupling the ultrathin ZnIn2S4 with few-layered Ti3C2Tx via the electrostatic self-assembly strategy. The 2D/2D Ti3C2Tx/ZnIn2S4 heterostructure possesses larger contact area and strong electronic interaction to promote the charge carrier transfer at the interface, and the sulfur vacancy on the ZnIn2S4 acting as the electron trap further enhances the separation of the photoinduced electrons and holes. As a consequence, the optimal 2D/2D Ti3C2Tx/ZnIn2S4 composite exhibits a high photocatalytic hydrogen evolution rate of 148.4 mu mol h(-1), which is 3.6 times and 9.2 times higher than that of ZnIn2S4 nanosheet and flower-like ZnIn2S4, respectively. Moreover, the stability of the ZnIn2S4 is significantly improved after coupling with the few-layered Ti3C2Tx. The characterizations and density functional theory calculation demonstrate that the synergistic effect of the sulfur vacancy and Ti3C2Tx cocatalyst can greatly promote the electrons transfer from ZnIn2S4 to Ti3C2Tx and the separation of photogenerated charge carriers, thus enhancing the photocatalytic hydrogen evolution from water.