CdS quantum dots and tungsten carbide supported on anatase-rutile composite TiO₂ for highly efficient visible-light-driven photocatalytic H₂ evolution from water

Developing efficient photocatalysts with noble-metal-free co-catalysts for visible-light-driven photocatalytic H₂ evolution from water is appealing yet remains challenging. Herein, by supporting CdS QDs with diameters smaller than 5 nm and tungsten carbide (WC) on TiO₂, a CdS/WC/TiO₂ photocatalyst was fabricated for visible-light-driven photocatalytic H₂ evolution from aqueous solution containing lactic acid as an electron donor. The optimal H₂ evolution rate on CdS/WC/TiO₂ (624.9 μmol h^-1) is comparable to the H₂ evolution rate on CdS/Pt/TiO₂ (636.2 μmol h^-1), indicating that WC is a good candidate to substitute Pt as the co-catalyst. Formation of an anatase-rutile composite TiO₂ with a rutile content of 68.7% makes great contribution to the efficient H₂ evolution on CdS/WC/TiO₂. The rutile-anatase composite TiO₂ promotes the separation of the photogenerated electron-hole pairs and thereby benefits the efficient H₂ evolution reaction. The present work is expected to be helpful in designing efficient noble-metal-free photocatalysts for H₂ evolution from visible-light-driven photocatalytic water splitting.