Efficient visible-light-driven photocatalytic hydrogen production over a direct Z-scheme system of TaON/Cd0.5Zn0.5S with a NiS cocatalyst

In this work, a series of samples of porous TaON decorated on Cd0.5Zn0.5S (ZCS) nanoparticles were successfully prepared as direct Z-scheme system. The photocatalytic evolution of H2 with a high efficiency was explored using NiS decorated with TaON sensitized ZCS nanocomposites (NiS-TaON/ZCS) and Na2SO3/Na2S as sacrificial reagents. The results showed that 0.5 wt% NiS deposited on the surface of the 4 wt% TaON-ZCS nanocomposites could reach the highest photocatalytic H2 evolution rate of 34.8 mmol h-1 g-1 with a maximum quantum yield of about 25.5% under 420 nm monochromatic light. The activity of photocatalyst TaON-ZCS for photocatalytic H2 evolution is higher than that of either pure ZCS or TaON. This high photocatalytic performance is ascribed firstly to the hierarchical structure of the coupled semiconductor system; secondly to the efficient transfer and separation of photogenerated charge carriers with NiS as a cocatalyst, which could serve as an electron collector.