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

In this work, oxygen vacancies were introduced onto the surface of BiFeO3 nanoparticles by NaBH4 reduction method to yield oxygen-deficient BiFeO3-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 BiFeO3-x nanoparticles. The photocatalytic activity of as-prepared BiFeO3-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 BiFeO3-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 BiFeO3-x sample exhibits good photocatalytic reusability.