On the synthesis and photochemical studies of nanostructured TiO 2 and TiO 2 admixed VO2 photoelectrodes in regard to hydrogen production through photoelectrolysis

Abstract

A new photoelectrode system TiO 2(ns)–VO 2 for photoassisted electrolysis of water is described. The nanostructured TiO 2 photoelectrode was prepared by the hydrolysis of titanium-tetraisopropoxide followed by deposition of thin film by spin coating. To prepare the TiO 2(ns)–VO 2 photoelectrode, vanadium film was deposited on the TiO 2(ns) film and subsequently oxidized in O 2 ambient. The TiO 2(ns)–VO 2 photoelectrode exhibited enhanced photovoltage and photocurrent of 680 mV and 11.0 mA cm −2, respectively, whereas the TiO 2(ns) presented 540 mV and 3.2 mA cm −2, respectively. X-ray and S.E.M studies were carried out to monitor the surface and bulk characteristics of the TiO 2(ns)–VO 2 photoelectrode. The rate of hydrogen production under photoelectrolysis was found to be 6 l h −1 m −2 for the TiO 2(ns) and ∼13.0 l h −1 m −2 for the TiO 2(ns)–VO 2 photoelectrode. The TiO 2(ns) photoelectrode shows the improvement in the PEC characteristics due to higher quantum yield resulting from the structured nature of the material. The PEC improvement in the TiO 2(ns)–VO 2 photoelectrode is due to the increase of range of absorption and the decrease of energy gap. © 1999 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.