Photochemical synthesis of bimetallic CuNiSx quantum dots onto g-C3N4 as a cocatalyst for high hydrogen evolution.

In the application of graphitic carbon nitride photocatalytic hydrogen production, utilizing transition-metal sulfides instead of noble metals as cocatalysts has broad research prospects. Among them, nickel sulfide is favored by researchers due to its easy preparation, low cost, chemical stability, and excellent photocatalytic performance. Unfortunately, the strong sulfur–hydrogen bonds suppress its development. In this study, we successfully fabricated bimetallic CuNiSx quantum dots onto graphitic carbon nitride by the photochemical deposition method; such a small size can expose more active S sites on the edge. Simultaneously, the introduction of Cu2+ into NiSx can slightly modulate the electronic structure of Ni and S centers, thus weakening the sulfur–hydrogen bonds. Consequently, the average hydrogen evolution rate of CN/CuNiSx QDs achieved 1061 μmol h−1 g−1, which is 4.3 times than that of CN/NiSx QDs (246 μmol h−1 g−1). This research provides a new scenario to design bimetallic sulfide cocatalysts for H2 evolution. [ABSTRACT FROM AUTHOR]