Solar photocatalytic generation of hydrogen from hydrogen sulphide using CdS-based photocatalysts

Laboratory-scale feasibility studies on solar photocatalytic generation of hydrogen (H-2) from Na2S/Na2SO3 solution by using CdS-based photocatalysts have been carried out in a batch solar photocatalytic reactor of 300 ml capacity. Three CdS-based photocatalytic mixtures [viz. CdS/ZnS, (CdS/ZnS)/Ag2S and (CdS/ZnS)/ Ag2S + (RuO2/TiO2)] were synthesized by adding wide band-gap semiconductors (ZnS and TiO2), promoters (Ag2S) and metal dopants (RuO2), and the activities of the three photocataIytic mixtures were evaluated. H-2 generation was found to be a maximum of 392 ml/g/h for the photocatalytic mixture of (CdS/ZnS)/Ag2S + (RuO2/TiO2) whereas it was only 213 ml/g/h for the photocatalytic mixture of CdS/ZnS. Thus, the solar photocatalytic generation of H-2 from Na2S/Na2SO3 solution using (CdS/ZnS)/Ag2S + (RuO2/TiO2) was found to be feasible.