Synthesis of Ag2O/NaNbO3 p-n junction photocatalysts with improved visible light photocatalytic activities

Ag2O/NaNbO3 p-n junction photocatalysts with improved visible light photocatalytic activities for Rhodamine B were synthesized by a simple precipitation method. The structures, morphologies, optical and visible-light photocatalytic properties of as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. Experimental results showed that Ag2O/NaNbO3 composites with different weight ratios of Ag2O to NaNbO3 (1:1, 3:1, 5:1, 7:1, 9:1) were successfully obtained. Compared with the pure Ag2O and NaNbO3 samples, as-synthesized Ag2O/NaNbO3 composites exhibit improved photodegradation performances for Rhodamine B under visible light irradiation. The composite with a Ag2O/NaNbO3 weight ratio of 7:1 shows the best photoactivity. The enhanced photodegradation performance of Ag2O/NaNbO3 can be attributed to the efficient separation of photo generated electrons and holes due to the construction of p-n junction of p-Ag2O and n-NaNbO3. Moreover, the primary active species in the photodegradation and the plausible photocatalytic mechanism scheme were studied. (C) 2017 Elsevier B.V. All rights reserved.