Electrodeposited p-type Cu2O as photocatalyst for H2 evolution from water reduction in the presence of WO3

Different p-type Cu2O powders were prepared from electrodeposition and subjected to analysis of their photocatalytic activity in water reduction. The electrodeposited Cu2O powders were obtained by scraping the deposited films off the substrate. Under illumination the Cu2O powders alone were not able to catalyze H2 generation from water reduction. However, these Cu2O powders exhibited photocatalytic activity in H2 generation when they were coupled with n-type WO3 in suspensions. The coupling was made to avoid back reactions of the photo-induced charges. The electrodeposited Cu2O powders showed higher photocatalytic activity than a commercially available Cu2O powder. The suspension containing electrodeposited Cu2O with a strong [1 1 1] orientation gave a larger amount of H2 evolution than that containing Cu2O with a [1 1 0] orientation. Appropriate crystalline-texture tuning, as well as charge delocalization promotion, is looked to as the key issue for efficient H2 generation from water reduction over p-type Cu2O photocatalysts.