Activity of cadmium sulfide photocatalysts for hydrogen production from water: Role of support

Alumina-supported cadmium sulfide photocatalysts for reduction of water to hydrogen were prepared by different techniques and characterized. The band gap, the dispersion of cadmium sulfide, and the contact between cadmium sul fide and alumina are affected by the preparation technique. Those preparati on techniques that promote better dispersion of cadmium sulfide and give ri se to a chemical interaction between cadmium sulfide and alumina impart a s uperior activity to the catalyst. The chemical interaction leads to decorat ion of cadmium sulfide surface by alumina which results in an intimate cont act between them. Catalyst prepared by coprecipitation shows the intimate c ontact but has a poor dispersion of cadmium sulfide, whereas impregnation o f alumina hydrogel results in a catalyst having both intimate contact betwe en alumina and cadmium sulfide and better dispersion of cadmium sulfide; co nsequently, this results in enhanced activity.