A film of rutile TiO2 pillars with well-developed facets on an alpha-Ti substrate as a photoelectrode for improved water splitting

A photoelectrode of single-crystal rutile TiO2 pillars with well-developed facets shows a 2.5 times higher capability of water splitting at 0.3 V than a conventional anatase TiO2 nanotube array electrode. The improvement is attributed to the synergistic effects of the high crystallinity of single-crystal rutile pillars, the exposed high-energy {011} and {111} as the reactive facets of water oxidation reaction and the extended light absorption range by ca. 23 nm.