Controlled preparation of hollow Zn0.3Cd0.7S nanospheres modified by NiS1.97 nanosheets for superior photocatalytic hydrogen production.

Abstract Developing durable and efficient photocatalysts for H2 evolution is highly desirable to expedite current research on solar-chemical energy conversion. In this work, a novel photocatalytic H2 evolution system based on Zn0.3Cd0.7S/NiS1.97 nanocomposite was rationally designed for the first time. In this advanced composite structure, NiS1.97 nanosheets as a co-catalyst were intimately coupled to the inner surface of the hollow spherical Zn0.3Cd0.7S. The construction of the hollow spherical shell shortened the distance of charge migration to the surface site and increased the multiple absorption of incident light. The introduction of NiS1.97 nanosheets increased the light absorption capacity of the composite system and also greatly improved the separation and migration behavior of photo-generated carriers due to its narrower band gap and relatively low conduction band position, which had been confirmed by DRS, EIS and PL. As a result, the hollow Zn0.3Cd0.7S/NiS1.97 composite material exhibited excellent photocatalytic activity. At the loading amount of NiS1.97 up to 15 at.%, the hollow Zn0.3Cd0.7S/NiS1.97 composite exhibited the best photocatalytic activity with a corresponding H2 production rate of 22.637 mmol g-1h−1, which was 1.42 times and 1.85 times that of hollow Zn0.3Cd0.7S and solid Zn0.3Cd0.7S, respectively. Moreover, this novel catalyst also displayed a long-term stability without apparent debasement in H2 evolution activity. It is expected that this work could provide new inspiration to the design and development of other highly active photocatalytic systems for water splitting.