Controlled preparation of β-Bi2O3/Mg–Al mixed metal oxides composites with enhanced visible light photocatalytic performance

Abstract

In this study, the β-Bi2O3/Mg–Al mixed metal oxides (MMO) composites were controllably prepared by a practical and low-cost method. The as-prepared composites were analyzed by XRD, SEM, TEM and UV–Vis diffuse reflectance spectra. The results showed that the Bi2O3 in the composites is β phase with enhanced photocatalytic activity, while the pure Bi2O3 is α phase, and the β-Bi2O3/Mg–Al MMO composites showed obviously red-shifted light absorption performance. Importantly, the β-Bi2O3/Mg–Al MMO composites have significantly improved photocatalytic degradation performance of methylene blue and p-chlorophenol under visible light irradiation. The reaction rate constants for the photodegradation of methylene blue and p-chlorophenol are 0.04081 min−1 and 0.01558 min−1, respectively. The Bi2O3 exists in β phase, and the synergistic effect between β-Bi2O3 and Mg–Al MMO is the main reason for the obvious improvement of photocatalytic performance, which is beneficial for the separation of photogenerated electrons and holes.