Controlling Carrier Separation by Ag2S Decoration on P-CdS Nanorods for Enhanced Photocatalytic Hydrogen Evolution

The separation of photo-generated carriers in heterojunctions plays a crucial role in regulating the built-in electric field. The design of materials with directional migration characteristics inside the bulk phase and at the interface between the two phases is of great significance for studying photocatalytic hydrogen evolution. The P-CdS/Ag₂S composite photocatalytic system prepared in this study was doped with P element by heating CdS and NaH₂PO₂ in a muffle furnace, resulting in the directed migration of photo-generated charges in the prepared sample driven by an internal electric field. By in-situ deposition of Ag₂S on the surface of P-CdS, a Janus heterojunction was prepared to enhance the transfer of charge carriers at the phase interface. The hydrogen evolution rate of P-CdS/Ag₂S is 12.44 mmol·h⁻¹·g⁻¹, which is 30 times higher than that of the previously prepared pure CdS sample (0.411 mmol·h⁻¹·g⁻¹). This significant improvement in photocatalytic performance is attributed to the doping of P element and the in-situ loading of Ag₂S co-catalyst, which together promote the effective separation and transport of photogenerated charge carriers, thereby enhancing the photocatalytic activity of the material. This work is of great significance for exploring the charge-directed transfer problem of sulfide photocatalysts in the field of photocatalytic hydrogen evolution.

Graphical Abstract