TiO2 corrosion during water photocleavage using Rh/TiO2 suspensions

Abstract

The absence of O₂ evolution during water photocleavage experiments using basic aqueous suspensions of Rh/TiO₂ photocatalysts, even after long irradiation periods (ca. 60 h), as well as the capacity of these catalysts to photo-adsorb O₂, have been examined in terms of formation of peroxo species which remain at the TiO₂ support thus leading to its progressive corrosion giving a thick layer of a titanium hydroxyperoxo-like compound. The role of this oxidized layer in the progressive decay observed in the rate of H₂ photoproduction as well as the possibility of regeneration of the original photoactivity by bubbling an inert gas through the suspensions are examined.