Uniform-embeddable-distributed Ni 3 S 2 cocatalyst inside and outside a sheet-like ZnIn 2 S 4 photocatalyst for boosting photocatalytic hydrogen evolution.

The rational cocatalyst design is considered a significant route to boost the solar-energy conversion efficiency for photocatalytic H generation. However, the traditional cocatalyst-loading on the surface of a photocatalyst easily leads to scarce exposed active sites induced by the agglomeration of cocatalysts and a hindrance of the light absorption of the photocatalyst, thus significantly limiting the enhancement of the photocatalytic H-generation performance. Herein, a new concept of uniform-embeddable-distributed cocatalysts is put forward. Consequently, uniform-embeddable-distributed cocatalysts of NiS were designed and constructed inside and outside of the nanosheet-like ZnInS photocatalyst to form a NiS/ZnInS binary system (UEDNiS/ZIS). The unique uniform-embeddable-distributed NiS cocatalyst (UEDNiS) could provide abundant exposed active sites, facilitate the spatial separation and ordered transfer of charges inside and outside of ZnInS nanosheets, and reduce the hydrogen-adsorption free energy for photocatalytic H-generation reactions. As a result, UEDNiS/ZIS exhibited a high photocatalytic H-generation rate of 60 μmol h under visible-light irradiation, almost 7.8 and 2.8 times higher than pristine ZnInS and the traditional surface-loaded NiS/ZnInS (TSLNiS/ZIS), respectively. This work represents a new cocatalyst-design approach to realize high-efficiency hydrogen evolution in binary heterostructured photocatalytic systems.