Water decomposition on TiO2-SiO2 and RuS2/TiO2-SiO2 photocatalysts:: the effect of electronic characteristics

Synergistic effects in terms of photocatalytic activity and electronic properties such as band gap energy, flat-band potential and doping density were observed on atomically mixing TiO2 and SiO2 by sol-gel method. Hydrogen evolution was remarkably enhanced over the optimal RuS2 loading (1 wt%) on TiO2-SiO2, which could be successfully explained by the charge transfer mechanism. Hydrogen seems to produce on the RuS2 surface by the photo-excited electrons transferred from TiO2-SiO2 due to the significant difference of flat-band potentials. Meanwhile, oxygen might be evolved by the holes on TiO2-SiO2 or on the RuS2 surface, retarding the recombination of photo-excited electrons and holes. (C) 2003 Elsevier B.V. All rights reserved.