Novel photocatalysts based on Cd1−xZnxS/Zn(OH)2 for the hydrogen evolution from water solutions of ethanol

Multiphase photocatalysts Pt/Cd1−xZnxS/ZnO/Zn(OH)2, Pt/Cd1−xZnxS/ZnO, and Pt/Cd1−xZnxS/Zn(OH)2 were synthesized by a new two-step technique. The photocatalysts were characterized by a wide range of experimental techniques: X-ray diffraction, high-resolution transmission electron microscopy combined with energy-dispersive X-ray spectroscopy, low-temperature N2 adsorption/desorption, and UV/VIS spectroscopy. The photocatalytic activity was tested in a batch reactor in the reaction of H2 evolution from aqueous solutions of ethanol under visible light irradiation (λ > 420 nm). The highest achieved photocatalytic activity was 2256 μmol H2 per gram of photocatalyst per hour; the highest quantum efficiency was 10.4%. The activity of Pt/Cd1−xZnxS/Zn(OH)2 was higher than that of Pt/Cd1−xZnxS/ZnO/Zn(OH)2 and Pt/Cd1−xZnxS/ZnO. The explanation of enhanced activity of zinc–cadmium sulfide/ε-zinc hydroxide based on quantum calculations was suggested.