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.