Photogeneration of hydrogen from water over an alumina-supported ZnS–CdS catalyst

Abstract

The rate of hydrogen generation from water with an alumina-supported mixed semiconductor catalyst (ZnS–CdS/Al₂O₃) has been found to be much higher than those from water with singly supported catalysts (ZnS/Al₂O₃ and CdS/Al₂O₃) under irradiation by both u.v. and visible light. The activity is not improved by the physical mixture of these singly supported catalysts even when the amounts of ZnS and CdS are the same as those present in the ZnS–CdS/Al₂O₃. The significant improvement in the rate of hydrogen production over ZnS–CdS/Al₂O₃ catalyst is attributed to the intimate contact between ZnS and CdS particles that results from the deposition of fine ZnS particles over the CdS surface. Sites for hydrogen production seem to be newly generated on these contacting regions.