title: Efficient Suppression of Electron-Hole Recombination in Oxygen-Deficient Hydrogen-Treated TiO2Nanowires for Photoelectrochemical Water Splitting.
abstract: There is an increasing level of interest in the use of black TiO2prepared by thermal hydrogen treatments (H:TiO2) due to the potential to enhance both the photocatalytic and the light-harvesting properties of TiO2. Here, we examine oxygen-deficient H:TiO2nanotube arrays that have previously achieved very high solar-to-hydrogen (STH) efficiencies due to incident photon-to-current efficiency (IPCE) values of >90% for photoelectrochemical water splitting at only 0.4 V vs RHE under UV illumination. Our transient absorption (TA) mechanistic study provides strong evidence that the improved electrical properties of oxygen-deficient TiO2enables remarkably efficient spatial separation of electron-hole pairs on the submicrosecond time scale at moderate applied bias, and this coupled to effective suppression of microsecond to seconds charge carrier recombination is the primary factor behind the dramatically improved photoelectrochemical activity.
authors.affiliation: Department of Chemistry, Imperial College London , Exhibition Road, London SW7 2AZ, United Kingdom.
authors.forename: Federico M
authors.initials: FM
authors.lastname: Pesci
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Cruz , Santa Cruz, California 95064, United States.
authors.forename: Gongming
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Imperial College London , Exhibition Road, London SW7 2AZ, United Kingdom.
authors.forename: David R
authors.initials: DR
authors.lastname: Klug
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Cruz , Santa Cruz, California 95064, United States.
authors.forename: Yat
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Chemistry and Stephenson Institute for Renewable Energy, The University of Liverpool , Liverpool L69 7ZD, United Kingdom.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Cowan