The influence of the sacrificial agent nature on transformations of the Zn(OH) 2 /Cd 0.3 Zn 0.7 S photocatalyst during hydrogen production under visible light.

Photocatalysts based on zinc hydroxide and a solid solution of CdS and ZnS were prepared via the precipitation method and used for photocatalytic hydrogen production from aqueous solutions of inorganic (Na 2 S/Na 2 SO 3 ) and organic (ethanol) sacrificial agents. The photocatalysts were tested in cyclic experiments for hydrogen evolution and studied using X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy, high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) techniques. Different transformations of the β-Zn(OH) 2 co-catalyst were observed in the presence of inorganic and organic sacrificial agents; namely, ZnS was formed in Na 2 S/Na 2 SO 3 solution, whereas the formation of ε-Zn(OH) 2 was detected in solution with ethanol. The composite Zn(OH) 2 /Cd 1- x Zn x S photocatalysts have great potential in various photocatalysis processes ( e.g. , hydrogen production, CO 2 reduction, and the oxidation of organic contaminants) under visible light.