Manipulation of cuprous oxide surfaces for improving their photocatalytic activity

Manipulating the surface characteristics of metal oxide electrodes allows the properties of the interface between electrodes and the electrolyte to be controlled and can lead to improvements in both efficiency and reliability of the electrodes. In this study, the facets exposed on the surfaces of Cu2O photoelectrodes were manipulated by controlling the pH of the bath during Cu2O film electrodeposition. The Cu2O film with (100)-type facets, deposited at a bath pH of 12, produced a photocurrent 19 times higher than that of the film deposited at pH 8.3 and possessing (111) facets. In addition, inverse-opalstructured Cu2O films were electrodeposited in alkali solutions using templates of polystyrene beads; these films exhibited even higher photocatalytic activities than the planar ones. The templated, three-dimensional (3D) Cu2O film deposited at pH 12 produced a photocurrent 2.14 times higher than that generated by the planar Cu2O film deposited at the same pH; this was a result of the greater surface area and higher light absorption of the 3D film.