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

Ag 2 O/Bi 2 O 3 microspheres were successfully synthesized by a facile co-precipitation hydrothermal method in the presence of surfactant polyvinylpyrrolidone (PVP). X-ray diffraction confirmed that Ag 2 O/Bi 2 O 3 was made up of the cubic Ag 2 O phase and the tetragonal Bi 2 O 3 phase. Scanning electron microscopy and transmission electron microscopy showed that the synthesized Ag 2 O/Bi 2 O 3 microspheres were assembled by radially grown nanosheets with the thickness of about 50   nm. In comparison with N-doped TiO 2 , Bi 2 O 3 and Ag 2 O, the Ag 2 O/Bi 2 O 3 composites showed much higher efficiency for photodegradation of Rhodamine B (RhB) under visible light irradiation ( λ ≥420   nm). Among the Ag 2 O/Bi 2 O 3 composites, the sample with 0.3   mol fraction of Ag 2 O exhibited the highest photocatalytic activity. The excellent photocatalytic activity of Ag 2 O/Bi 2 O 3 may be ascribed to the strong visible light absorption resulting from the quantum dot sensitization of Ag 2 O and the efficient separation of photogenerated electron–hole pairs through Ag 2 O/Bi 2 O 3 heterojunction . The possible photocatalytic mechanism was proposed based on band gap structure analysis and the reaction effects by adding the radical scavengers.