Noble metal-free bimetallic phosphide-decorated Zn_0.5Cd_0.5S with efficient photocatalytic H₂ evolution

The rapid recombination of charge carriers in semiconductor-based photocatalysts results in a low photocatalytic activity. Co-catalysis is considered a promising strategy to improve the photocatalytic performance of semiconductors. In this study, a bimetallic phosphide was grown by a facile in situ growth method. Loading the cocatalyst (7 wt% NiCoP) leads to activity enhancement by a factor of approximately 27 times in the visible-light-driven hydrogen evolution relative to the pristine Zn_0.5Cd_0.5S. The photocatalysis shows a high hydrogen evolution rate of 19.5 mmol g^-1 h^-1, which is much higher than that of the single metal phosphide (Ni₂P: 7.0 mmol g^-1 h^-1; CoP: 8.1 mmol g^-1 h^-1) and 7 wt% Pt modified Zn_0.5Cd_0.5S (0.3 mmol g^-1 h^-1). Its apparent quantum efficiency reaches 41.6% at 420 nm. Moreover, the photocatalyst exhibits a remarkable photostability for five consecutive cycles of photocatalytic activity measurements with a total reaction time of 15 hours. The excellent photocatalytic activity of the photocatalyst was attributed to the in situ-formed NiCoP cocatalyst, which not only acts as a reactive site but also accelerates the separation of charge carriers.