Microwave-synthesized KNbO3 perovskites: photocatalytic pathway on the degradation of rhodamine B

In this work, KNbO3 perovskite nanostructures were prepared at different Nb2O5:KOH molar ratios via microwave-assisted hydrothermal synthesis. The structural and optical properties of the samples were characterized by XRD, SEM, TEM, diffuse reflectance, and photoluminescence analysis. The [1:16] sample showed an improved electron-hole separation when compared to the other synthetic pathways. Photocatalytic activities of the materials in the degradation of rhodamine B were also evaluated. The results indicate that the perovskite with the molar ratio [1:16] showed higher photocatalytic efficiency in the degradation of rhodamine B, with a 23-fold decrease in the initial concentration. Such improved performance is accounted for by its large values of specific surface area and a more efficient conversion of UV photons into effective charge carriers. Photodegradation intermediates were identified by micrOTOF-Q III liquid chromatography, which indicated a large amount of N-de-ethylated cleavage products and simple organic acids, thus demonstrating the excellent applicability potential of these KNbO3 ferroelectrics in the degradation of organic pollutants in wastewater.