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

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 CaIn2S4 catalysts combined with Ni2P, which acts as the co-catalyst, for boosting photocatalytic hydrogen evolution under visible light. The integrated system of the Ni2P/CaIn2S4 composite exhibited high efficiency and durability, which were even higher than those of Pt decorated catalysts. The promoting effect of Ni2P 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 Ni2P for the movement of photo-generated charges during the photocatalysis process is proposed for the first time. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.