Coupling amorphous WO3 with WP as a cocatalyst for efficient dye-sensitizated photocatalytic hydrogen evolution.

Tungsten phosphide (WP) as an excellent hydrogen evolution reactions (HER) catalyst has attracted widespread attention, but its HER activity is low in alkaline media due to high water dissociation barrier. Herein, noble-metal-free cocatalyst WP/WO 3 composite was synthesized by adjusting the P/W molar ratio in the raw material using a simple solid phosphidation reaction. The structure, morphology, composition, and optoelectronic properties of the as-synthesized samples were characterized by XRD, SEM, TEM, XPS, UV–vis DRS, PL techniques, and electrochemical methods. Under visible light irradiation (λ ≥ 420 nm), the photocatalytic HER activities of the as-prepared samples using Eosin-Y (EY) dye as a sensitizer and trimethylamine (TMA) as an electron donor were investigated. The result shows that WP/WO 3 composite as a cocatalyst exhibits excellent photocatalytic HER activity and good stability. The highest apparent quantum yield (AQY) reaches 32.8 %. The presence of amorphous WO 3 in crystalline WP can improve the separation efficiency of photogenerated electrons and holes, reduce HER overpotential, and promote the dissociation of H 2 O in alkaline media. Therefore, the photocatalytic HER activity of WP/WO 3 composite is higher than that of single crystalline WP. [Display omitted] • WP/WO 3 composite was prepared by adjusting the P/W molar ratio in the raw material. • WP/WO 3 composite exhibits high dye-sensitized photocatalytic HER activity. • WO 3 coupling with WP promotes the separation of photocarriers and H 2 O dissociation. • The AQY of 32.8 % at 420 nm is achieved under the optimized conditions. [ABSTRACT FROM AUTHOR]