A comparative study of CdS-based semiconductor photocatalysts for solar hydrogen production from sulphide + sulphite substrates

Abstract Different types of CdS-based photocatalysts have been prepared, characterized and tested for hydrogen evolution from a sulphide + sulphite solution. The benefit of the thermal treatment of CdS in air, argon, hydrogen sulphide or hydrogen atmospheres, as well as that of etching its surface, have been shown. The effects of adding to CdS a second semiconductor of smaller bandgap (Cu x S) or larger bandgap (TiO 2 ), or/and a catalytic material (Pt or RuO x ), have been studied. The best results have been obtained using particles of CdS of ≈ 1.4 ωm, treated at 400°C in air atmosphere and etched with concentrated HNO 3 , and on which 0.4% by weight of Pt was deposited.