Synthesis of RuO2-loaded BaTinO2n+1 (n=1, 2 and 5) using a polymerizable complex method and its photocatalytic activity for the decomposition of water

A polymerizable complex (PC) technique was utilized to prepare fine powders of high purity BaTinO2n+1 with n=1, 2 and 5 at lower temperatures than those used for the ordinary solid-state reaction procedure. The formation of pure BaTinO2n+1 occurred when precursors obtained from PC-derived gel materials were heat-treated at 800-900degreesC in static air for 2 h. BaTinO2n+1 powders were subsequently converted to RuO2-loaded materials, and their photocatalytic activities for the decomposition of water were examined. While the RuO2-BaTi2O5 (n=2) and RuO2-BaTi5O2N+1 (n=5) materials exhibited photocatalytic activity for water decomposition into H-2 and O-2 in approximately stoichiometric amounts (H-2 :O-2=2:1) under UV light irradiation with specific hydrogen gas evolution rates of 125 and 52 mumol h(-1) g(-1), respectively, the RuO2-BaTiO3(n=1) exhibited a very low activity of less than 1 mumol h(-1) g(-1). The lack of a significant occurrence of photocatalysis in BaTiO3 was explained in terms of its crystal structure possessing only a very small polyhedral distortion.