Metalloid Ni2P and its behavior for boosting the photocatalytic hydrogen evolution of CaIn2S4

Abstract The development of high-efficiency and low-cost photocatalysts in photocatalytic H 2 evolution systems from water remains challenging. The substitution of a noble metal as the co-catalyst is still one of the important and meaningful issues in this field. Herein, we report a series of CaIn 2 S 4 catalysts combined with Ni 2 P, which acts as the co-catalyst, for boosting photocatalytic hydrogen evolution under visible light. The integrated system of the Ni 2 P/CaIn 2 S 4 composite exhibited high efficiency and durability, which were even higher than those of Pt decorated catalysts. The promoting effect of Ni 2 P can be ascribed to its excellent reductive ability and analogous metallic character, which can accelerate the transfer and consumption of the photo-generated electrons. Moreover, based on the surface photo-voltage technique and electrochemical tests, the unique mechanism of Ni 2 P for the movement of photo-generated charges during the photocatalysis process is proposed for the first time.