Photocatalytic water splitting using modified GaN:ZnO solid solution under visible light: long-time operation and regeneration of activity

Tomoyuki Ohno; Lu Bai; Takashi Hisatomi; Kazuhiko Maeda; Kazunari Domen

doi:10.1021/ja302479f

Photocatalytic water splitting using modified GaN:ZnO solid solution under visible light: long-time operation and regeneration of activity

J Am Chem Soc. 2012 May 16;134(19):8254-9. doi: 10.1021/ja302479f. Epub 2012 May 2.

Authors

Tomoyuki Ohno¹, Lu Bai, Takashi Hisatomi, Kazuhiko Maeda, Kazunari Domen

Affiliation

¹ Department of Chemical System Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.

PMID: 22524238
DOI: 10.1021/ja302479f

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.