Structure Sensitivity of Nano-structured CdS/SBA-15 Containing Au and Pt Co-catalysts for the Photocatalytic Splitting of Water

Photocatalysts containing nanocrystallites of cadmium sulphide dispersed in the channels of mesoporous silicate SBA-15 exhibited enhanced activity for visible-light mediated splitting of water, as compared to bulk CdS. Whereas the incorporation of 1 wt.% Pt co-catalyst in CdS/SBA-15 led to a substantial increase in H2 yield, Au at similar loading resulted in marginally decreased activity. The results indicate that the photocatalytic activity of CdS crystallites is structure sensitive. Similarly, the role of a noble metal may be associated with the particle size dependent micro-structural features, rather than its electronic properties such as the work function or the heat of adsorption of reactant or product molecules.