Citric acid assisted solvothermal synthesis of BiFeO3 microspheres with high visible-light photocatalytic activity

A novel BiFeO3 photocatalyst in the shape of uniform microspheres has been synthesized by solvothermal process assisted with chelating effect of citric acid. The higher photoactivity of this catalyst than that of BiFeO3 via solid-state reaction for methylene blue (MB) degradation under visible-light irradiation is owing to the high crystallization of perovskite-type BiFeO3, high surface area with hollow structure, narrow band gap energy of 2.1 eV, and the promotion of separation of photo-induced electrons and holes. Additionally, no decrease of activity after being reused repetitively for five times is indicative of the high hydrothermal stability of BiFeO3 particles without crystal phase transformation. (C) 2010 Elsevier B.V. All rights reserved.