Enhanced photocatalytic H2-production activity of CdxZn1−xS nanocrystals by surface loading MS (M = Ni, Co, Cu) species

To investigate the role of metal sulfides as co-catalyst for photocatalytic hydrogen production under visible light irradiation, we have loaded small amounts of transition-metal sulfides (MS), such as NiS, CoS and CuS, onto the surface of CdxZn1−xS solid solution. It can be found that the rate of H2 evolution over the MS/Cd0.4Zn0.6S was 5 times higher than that of the pure Cd0.4Zn0.6S, and is comparable to the Cd0.4Zn0.6S modified with 1 wt% platinum (Pt) co-catalysts. The MS/Cd0.4Zn0.6S photocatalysts were characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV–visible spectrophotometer (UV–vis), and photoluminescence (PL) spectroscopy. It can be speculated that the MS provided active sites for H2 production and caused the migration of excited electrons from Cd0.4Zn0.6S toward MS, leading to the enhancement of photocatalytic activity.