Controlled preparation of hollow ZnCdS nanospheres modified by NiS nanosheets for superior photocatalytic hydrogen production.

Developing durable and efficient photocatalysts for H evolution is highly desirable to expedite current research on solar-chemical energy conversion. In this work, a novel photocatalytic H evolution system based on ZnCdS/NiS nanocomposite was rationally designed for the first time. In this advanced composite structure, NiS nanosheets as a co-catalyst were intimately coupled to the inner surface of the hollow spherical ZnCdS. 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 NiS 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 ZnCdS/NiS composite material exhibited excellent photocatalytic activity. At the loading amount of NiS up to 15 at.%, the hollow ZnCdS/NiS composite exhibited the best photocatalytic activity with a corresponding H production rate of 22.637 mmol gh, which was 1.42 times and 1.85 times that of hollow ZnCdS and solid ZnCdS, respectively. Moreover, this novel catalyst also displayed a long-term stability without apparent debasement in H 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.