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

Abstract

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 800–900 °C 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–BaTi5O11 (n = 5) materials exhibited photocatalytic activity for water decomposition into H2 and O2 in approximately stoichiometric amounts (H2 ∶ O2 = 2 ∶ 1) under UV light irradiation with specific hydrogen gas evolution rates of 125 and 52 µmol h−1 g−1, respectively, the RuO2–BaTiO3(n = 1) exhibited a very low activity of less than 1 µmol 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.