Photochemical hydrogen production with platinized suspensions of cadmium sulfide and cadmium zinc sulfide modified by silver sulfide

An efficient hydrogen production can be achieved by irradiated suspensions of platinized CdS in solutions of S/sup 2 -/ and/or SO/sub 3//sup 2 -/ ions. However, the photocatalytic activity of CdS powders strongly depends on their specific surface area. However, coprecipitation of CdS with about 0.5-3 wt% silver sulfide or surface modification of CdS with a large specific surface area by silver ions permitted preparation of very active platinized photocatalysts. The enhancement of activity is not limited to the absorption range of CdS, but also results from a significant extension of the spectral response up to about 620 nm. Further improvement of the photoactivity can be achieved by doping the Ag/sub 2/S activated CdS powders with zinc sulfide. 77 references, 17 figures.