Enhancement of the Efficiency of g-C₃N₄ for Hydrogen Evolution by Bifunctionality of RuSe₂

Adding a cocatalyst to a semiconductor catalyst is often considered an effective measure to increase the efficiency of the photocatalytic hydrogen evolution reaction. Nowadays, noble metals are the state-of-the-art cocatalysts for the hydrogen evolution reaction. Due to their high cost and scarcity, it is imperative to develop cocatalysts prepared from cheap and abundant elements. Here, RuSe2 was used as an effective substitute for precious metal promoters such as Pt to enhance the efficiency of g-C3N4 for the hydrogen evolution reaction. A high efficiency of 13417.3 μmol·g–1·h–1 was obtained. It was 214 times higher than that of g-C3N4 and 2.8 times higher than that of 3%Pt/g-C3N4. Density functional theory calculations were performed. The (210) and (200) crystal faces of RuSe2 showed lower ΔGH* than Pt(111), indicating higher hydrogen evolution efficiency. Compared with the Pt cocatalyst, metallic RuSe2 cocatalysts exhibited superior performance. Meanwhile, the electrocatalytic activity was also investigated in an alkaline medium. It showed a decent electrocatalytic activity and high stability. These findings might provide a prototype to develop cheap and efficient cocatalysts for large-scale water splitting.