Photocatalytic H2 evolution by layered perovskite Ca3Ti2O7 codoped with Rh and Ln (Ln = La, Pr, Nd, Eu, Gd, Yb, and Y) under visible light irradiation

Layered perovskite Ca3Ti2O7 codoped with Rh and Ln (Ca(3-x)Ln(x)Ti(1.9)Rh(0.1)O(7); Ln = La, Pr, Nd, Eu, Gd, Yb, and Y; 0 <= x <= 0.15) was synthesized by a conventional solid-state reaction to investigate the effects of Rh and Lit codoping on the photocatalytic activity. Rh and Ln-codoped Ca3Ti2O7 exhibited a higher photocatalytic activity than Rh-doped Ca3Ti2O7 for H-2 production from an aqueous methanol solution under visible light irradiation (lambda > 420 nm). In addition, the induction period for H-2 production was shortened by codoping with Rh and Ln. The codoped elements helped control the oxidation state of Rh ions and suppressed the formation of oxygen defects, improving the activity of the Rh-doped Ca3Ti2O7 photocatalyst. (C) 2009 The Ceramic Society of Japan. All rights reserved.