Synchronously Enhancing Water Adsorption and Strengthening Se–Hads Bonds in Se-Rich RuSe2+x Cocatalyst for Efficient Alkaline Photocatalytic H2 Production

The alkaline H2-generation activity of RuSe2 materials is inhibited by its relatively inadequate water-adsorption ability and weak selenium–hydrogen (Se–Hads) bonds in photocatalytic water splitting. Herein, the water adsorption ability and Se–Hads bonds have been synchronously strengthened to improve the photocatalytic H2 evolution of TiO2 via creating electron-deficient Ruδ+ and Seδ+ sites in Se-rich amorphous RuSe2+x (RuSe2+x) nanodots. By a facile complexation-photodeposition pathway, Se-rich RuSe2+x nanodots (ca. 1.5 nm) are perfectly anchored onto TiO2 nanoparticles. Compared to the pristine TiO2 and conventional c-RuSe2/TiO2 materials, the constructed Se-rich RuSe2+x/TiO2(0.5 wt %) photocatalyst achieves an improved H2-generation rate of 227.42 μmol h–1 with releasing visual H2 bubbles in alkaline media. The experimental and theoretical studies support that the excess Se atoms in the Se-rich RuSe2+x nanodots induce the charge redistribution of Ru and Se atoms to form electron-deficient Ruδ+ and Seδ+ sites, which synchronously enhance water adsorption and strengthen Se–Hads bonds, thus boosting alkaline photocatalytic H2 production. This research delivers a significant approach to design high-performance materials for alkaline H2 production by double active-site regulation.