Synthesis of Ag2O–KNbO3 heterojunction photocatalysts with enhanced visible-light-responsive photocatalytic performance for sulfamethoxazole degradation

In this work, Ag2O–KNbO3 composites were fabricated successfully by an in-situ deposition method. The as-prepared 0.15Ag–Nb composite exhibited extremely improved photocatalytic activity for Sulfamethoxazole (SMZ) degradation under the irradiation of visible light compared to the corresponding pure KNO and Ag2O. The apparent rate constant k is 0.0603 min−1, which was 40 and 8 times as that of KNO and Ag2O, respectively. X-Ray diffractometer, transmission (or high resolution) electron microscope, X-ray photoelectron spectroscopy, photoluminescence spectroscopy, photocurrent, Electrochemical impedance spectroscopy and UV absorption spectrum are applied to investigate the crystal structure, morphology, chemical elements composition and states and optical property of the fabricated composites, respectively. Moreover, the degradation pathways of SMZ by 0.15Ag–Nb composite were deduced. The formation of Type Ⅰ heterojunctions between KNO and Ag2O greatly increased the separation of photo-induced holes and electrons, thus induced to the improved photocatalytic property of the as-prepared 0.15Ag–Nb composite.