Facile in-situ synthesis of α-NiS/CdS p-n junction with enhanced photocatalytic H2 production activity

Constructing active sites on photocatalysts is one of the most effective approaches for promoting photocatalytic H2 production activity. In this paper, a p-type semiconductor α-NiS is in-situ grown on an n-type semiconductor CdS by a simple solid state method, which results in a strong interfacial contact between α-NiS and CdS. Benefitting from the built-in electric field caused by a p-n junction, the photoinduced electrons of CdS and holes of α-NiS migrate to their interface and recombine rapidly, which results in the formation of a Z system. The more negative CB potential of α-NiS/CdS possesses stronger ability to reduce H+ to H2, thereby exhibiting higher photocatalytic H2 evolution activity. Furthermore, the strong interface contact is beneficial to the charge migration and promotes the charge separation efficiency. The H2 evolution rate of 1.0% α-NiS/CdS reaches 9.8 mmol h−1 g−1, corresponding to an AQY of 65.7% at λ = 420 nm.