Tio2 Protection Layer And Well-Matched Interfaces Enhance The Stability Of Cu2znsns4/Cds/Tio2 For Visible Light Driven Water Splitting

Cu2ZnSnS4-Based heterostructure materials present broad spectral absorption and a high absorption coefficient in the visible region; however, their photocatalytic activity and stability are still impeded due to photochemical corrosion. In this paper, Cu2ZnSnS4/CdS/TiO2, a double-heterojunction photocatalyst fabricated with a TiO2 protection layer and well-matched interface architecture, has been prepared by a multi-step liquid phase process. The chemically inert TiO2 protective layer on the catalyst surface restrained the catalyst photocorrosion induced by formed nascent O-2 and remarkably enhanced the catalyst stability during photocatalytic water splitting. Structural characterization and theoretical simulation indicated that both interfaces between Cu2ZnSnS4-CdS and CdS-TiO2 showed highly well-matched type-II alignment, which was beneficial to the separation and transfer of photoinduced charge pairs. The Cu2ZnSnS4/CdS/TiO2/Pt catalyst under visible light achieved photocatalytic water splitting and the H-2 evolution rate of the catalyst reached 8.76 mu mol g(-1) h(-1). The catalyst activity has been maintained in multi-cycle experiments without significant decay, and its stability has been confirmed by measuring the Cd2+ concentration in the catalyst dispersion using the ICP-OES method. This work can offer a new route to design more stable and efficient Cu2ZnSnS4-based heterostructure materials for solar-driven photocatalytic water splitting to produce H-2.