Hydrothermal synthesis of Ag2O/Bi2O3 microspheres for efficient photocatalytic degradation of Rhodamine B under visible light irradiation

Ag2O/Bi2O3 microspheres were successfully synthesized by a facile co-precipitation hydrothermal method in the presence of surfactant polyvinylpyrrolidone (PVP). X-ray diffraction confirmed that Ag2O/Bi2O3 was made up of the cubic Ag2O phase and the tetragonal Bi2O3 phase. Scanning electron microscopy and transmission electron microscopy showed that the synthesized Ag2O/Bi2O3 microspheres were assembled by radially grown nanosheets with the thickness of about 50 nm. In comparison with N-doped TiO2, Bi2O3 and Ag2O, the Ag2O/Bi2O3 composites showed much higher efficiency for photodegradation of Rhodamine B (RhB) under visible light irradiation (2 420 nm). Among the Ag2O/Bi2O3 composites, the sample with 0.3 mol fraction of Ag2O exhibited the highest photocatalytic activity. The excellent photocatalytic activity of Ag2O/Bi2O3 may be ascribed to the strong visible light absorption resulting from the quantum dot sensitization of Ag2O and the efficient separation of photogenerated electron hole pairs through Ag2O/Bi2O3 heterojunction. The possible photocatalytic mechanism was proposed based on band gap structure analysis and the reaction effects by adding the radical scavengers. (C) 2015 Published by Elsevier Ltd and Techna Group S.r.l.