Regulating interfacial morphology and charge-carrier utilization of Ti3C2 modified all-sulfide CdS/ZnIn2S4 S-scheme heterojunctions for effective photocatalytic H2 evolution

The separation efficiency of electrons and holes and the enhancement of the surface reductive reaction in the metal sulfide semiconductor photocatalysts are important factors in boosting photocatalytic H2 evolution from water. The control of both interface morphology and the charge–carrier utilization of metal sulfide-based photocatalysts can effectively improve the separation efficiency of electrons and holes and increase the surface reaction active sites, which are considered to be effective methods to improve the photocatalytic activity of semiconductors. Here, the Ti3C2 (Mxene) modified all-sulfide 2D/2D S-scheme heterojunction Ti3C2/ ZnIn2S4(ZIS)/CdS composite material was firstly synthesized by a two-step solvothermal method. The formation of all-sulfide S-scheme heterojunction improves the efficiency of electron-hole separation. The intimate 2D/2D van der Waals structure provides a strong interaction force and a large contact area to enhance charge transfer. The addition of 2D Ti3C2 forms the accumulation layer, reducing the recombination of electrons and holes. Under the synergistic promotion, the highest hydrogen production of the prepared Ti3C2/ZIS/CdS composite photocatalyst could reach 8.93 mmol/h/g. This work not only enriches the photocatalytic systems through integrating the ohmic junction and the 2D/2D all-sulfide S-scheme heterojunction, but also provides a satisfactory design strategy for engineering interfacial morphology and charge-carrier utilization.