Construction of Ag2S/WO3 Direct Z-Scheme Photocatalyst for Enhanced Charge Separation Efficiency and H2 Generation Activity

Efficient separation and utilization of the photoinduced charge is crucial to the photocatalytic H-2 generation reaction, especially for semiconductors with narrow band gap energies that suffer severe charge recombination. Herein, a novel Ag2S/WO3 direct Z-scheme photocatalyst was fabricated by depositing Ag2S nanoparticles (NPs) on hexagonal WO3 (h-WO3) nanorods (NRs) via a precipitation process, which can effectively prevent the agglomeration of Ag2S NPs, consequently shortening the charge migration pathway and reducing the recombination probability. Also, the Z-scheme mechanism further promotes the charge separation without crippling the redox ability of electron-hole pairs. In virtue of the synergistic effect between the morphology and the Z-scheme mechanism, the optimal Ag2S/WO3 photocatalyst exhibits a superior charge separation efficiency and similar to 4 times higher photocatalytic H-2 generation activity than that of Ag2S NPs alone. The present study provides a promising strategy to alleviate the charge recombination and improve the photoactivity of narrow band gap semiconductors by designing hybrid photocatalysts.