Enhanced Photocatalytic Activity of NaBH4 Reduced BiFeO3 Nanoparticles for Rhodamine B Decolorization

Abstract

In this work, oxygen vacancies were introduced onto the surface of BiFeO₃ nanoparticles by NaBH₄ reduction method to yield oxygen-deficient BiFeO_3-x samples. Comprehensive analysis on the basis of high-resolution transmission electron microscopy (HRTEM) observation and X-ray photoelectron spectrum (XPS) confirms the existence of surface oxygen vacancies on the BiFeO_3-x nanoparticles. The photocatalytic activity of as-prepared BiFeO_3-x samples was evaluated by the decolorization of rhodamine B (RhB) under simulated sunlight irradiation. The experimental results indicate that the photocatalytic activity of samples is highly related to the NaBH₄ reduction time, and the BiFeO_3-x sample reduced for 40 min exhibits the highest photocatalytic efficiency, which is much higher than that of pristine BiFeO₃ nanoparticles. This can be explained by the fact that the surface oxygen vacancies act as photoinduced charges acceptors and adsorption sites suppress the recombination of photogenerated charges, leading to an increasing availability of photogenerated electrons and holes for photocatalytic reaction. In addition, the obtained BiFeO_3-x sample exhibits good photocatalytic reusability.