Fabrication of Ag2O/KNbO3 heterojunction with high visible-light photocatalytic activity

Abstract

In the present work, a series of Ag2O/KNbO3 composite photocatalysts are prepared for the first time through an in situ growth method. The as-obtained samples are well characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, UV-vis absorption spectroscopy, and X-ray photoelectron spectroscopy. The photocatalytic properties of the samples are assessed by decomposition of rhodamine B (RhB) under visible-light excitation. The results demonstrate Ag2O/KNbO3 illustrated superior photocatalytic activity. The rate constant of RhB degradation over the optimal sample (Ag2O/KNbO3-6:1) exceeded 2.78 and 65 times higher than that of pure Ag2O and KNbO3, respectively. The improved photocatalytic activity could be due to the heterostructure of the catalyst, which enhance the visible light absorption capacity and the separation efficiency of photogenerated carriers. The quenching experiments of varied scavengers illustrated that •O2− and h+ were the primary active species in the decoloration of RhB.