LAUSR

Noble metals are usually worked as the cocatalyst for photocatalytic water splitting, but the rare and expensive properties narrowed their wide development. Transition metal sulfides have appeared to be promising non-noble metals cocatalysts in hydrogen evolution reaction (HER) to meet future energy demand. Meanwhile, many studies focus on the fabrication of bimetallic catalyst because of their more remarkably catalytic activity compared with monometallic substance. Herein, amorphous bimetallic cobalt nickel sulfide (CoNiSx) was fabricated to work as cocatalyst in photocatalytic H2 evolution reaction, which can couple with pristine graphitic carbon nitride (g-C3N4). CoNiSx-CN exhibits a larger specific surface area compared with g-C3N4, making it possess more reaction active sites. Moreover, the contacted interface in CoNiSx-CN composite photocatalyst contribute to higher separation efficiency of photogenerated carriers, which was proved by experimental and theoretical calculation. More importantly, the theoretical calculation also verified that CoNiSx-CN has relatively closer Gibbs free energy to zero than pure g-C3N4 and corresponding mono metallic cocatalysed g-C3N4. Therefore, the prepared CoNiSx-CN composite exhibited dramatically photocatalytic HER performance of 2.366 μmol mg-1 h-1, which is about 76-fold higher in comparison with pristine g-C3N4 and comparable to g-C3N4 with Pt as a cocatalyst under 420-nm light irradiation. This study reveals a promising and efficient bimetallic cocatalyst for photocatalytic H2 evolution reaction.