CsTaWO₆ as photoelectron platform by carbon nitride sensitizing toward enhanced charge carrier separation and photocatalytic activity

A series of CsTaWO₆/g-C₃N₄ composite photocatalysts were successfully prepared aiming to regulate the charge kinetics for spatial separating the photoinduced electrons and holes under visible light irradiation, which was ascribed to the matched band edge alignment of CsTaWO₆ and g-C₃N₄. Careful characterization on the as-prepared photocatalysts indicated the co-existent of g-C₃N₄ and CsTaWO₆ in the composite. Because of electronic structure match and fine interfacial contact, CsTaWO₆ anchored with g-C₃N₄ can enhance the visible light harvesting capacity and the photocatalytic activity toward hydrogen evolution was greatly improved with an optimized evolution rate of 7.5 μmol·g⁻¹·h⁻¹ and an excellent photocatalytic stability was achieved. The enhancement of photocatalytic activity was attributed to the fact that photoinduced electrons in the conduction band of g-C₃N₄ can be efficiently injected into the conduction band of CsTaWO₆, leading to spatial charge separation between g-C₃N₄ and CsTaWO₆, which can be confirmed by incident photocurrent responses and electrochemical impedance curves.