Enhanced photocarrier separation in conjugated polymer engineered CdS for direct Z-scheme photocatalytic hydrogen evolution

High efficiency hydrogen generation from water has been achieved in sulfide-polymer heterojunction. In this work, a novel direct Z-scheme CdS/polyimide heterojunction was fabricated by in situ growth of CdS nanoparticles on polyimide (PI) ultrathin nanosheets through solvothermal method. The highest activity achieved on 15%CdS/PI sample reaches to H-2-production rate of 613 mol h(-1) g(-1) under visible-light irradiation, which is nearly 5 and 60 times higher than that of neat CdS and 1%Pt/PI. Most importantly, the excellent photostability is also achieved over 15% CdS/PI. The enhanced photocatalytic performance and photostability can be attributed to the direct Z-scheme charge transfer in the intimate interfacial between CdS and PI, which accelerates the charges separation and effective suppress of the photocorrosion in CdS/PI heterojunction. The direct Z-scheme charge transfer mechanism is evidenced by in-situ XPS analysis and time-resolved fluorescence (TRPL) decay. This work highlights the role of polymer in constructing efficient sulfide/polymer heterojunction photocatalyst.