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 Ti₃ C₂ T_x /ZnIn₂ S₄ heterostructure is rationally designed by coupling the ultrathin ZnIn₂ S₄ with few-layered Ti₃ C₂ T_x via the electrostatic self-assembly strategy. The 2D/2D Ti₃ C₂ T_x /ZnIn₂ S₄ heterostructure possesses larger contact area and strong electronic interaction to promote the charge carrier transfer at the interface, and the sulfur vacancy on the ZnIn₂ S₄ acting as the electron trap further enhances the separation of the photoinduced electrons and holes. As a consequence, the optimal 2D/2D Ti₃ C₂ T_x /ZnIn₂ S₄ composite exhibits a high photocatalytic hydrogen evolution rate of 148.4 µmol h^-1 , which is 3.6 times and 9.2 times higher than that of ZnIn₂ S₄ nanosheet and flower-like ZnIn₂ S₄ , respectively. Moreover, the stability of the ZnIn₂ S₄ is significantly improved after coupling with the few-layered Ti₃ C₂ T_x . The characterizations and density functional theory calculation demonstrate that the synergistic effect of the sulfur vacancy and Ti₃ C₂ T_x cocatalyst can greatly promote the electrons transfer from ZnIn₂ S₄ to Ti₃ C₂ T_x and the separation of photogenerated charge carriers, thus enhancing the photocatalytic hydrogen evolution from water.