title: Photocatalytic water splitting using modified GaN:ZnO solid solution under visible light: long-time operation and regeneration of activity.
abstract: Overall water splitting using GaN:ZnO solid solution photocatalyst modified with Rh(2-y)Cr(y)O(3) nanoparticles as H(2) evolution cocatalysts under visible light (400 < λ < 500 nm) was examined with respect to long-term durability and regeneration of photocatalytic activity. The rate of visible light water splitting remained unchanged for 3 months (2160 h), producing H(2) and O(2) continuously at a stoichiometric amount. After 6 months of operation, a 50% loss of the initial activity occurred. Regeneration treatment of deactivated catalysts was attempted by reloading the Rh(2-y)Cr(y)O(3) cocatalyst. The degree of activity regeneration depended on the reloading amount. Up to 80% of the initial activity for H(2) evolution could be recovered under  optimal treatment conditions. It was also found that  deactivation of GaN:ZnO was suppressed to some extent by prior coloading of an O(2) evolution cocatalyst, which helped to suppress  oxidative decomposition of GaN:ZnO by valence band holes, thereby improving the durability.
authors.affiliation: Department of Chemical System Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Ohno
authors.forename: Lu
authors.initials: L
authors.lastname: Bai
authors.forename: Takashi
authors.initials: T
authors.lastname: Hisatomi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Maeda
authors.forename: Kazunari
authors.initials: K
authors.lastname: Domen