Photodegradation of Methylene Blue by LaFeO3/ZnO Nanocomposites under Visible and UV Light Irradiation

Abstract

Abstract In this study, LaFeO3/ZnO nanocomposites with different molar ratios of ZnO (0.1, 0.3, 0.5, and 1) have been prepared using the sol-gel method. The structural and elemental analyses of the samples were measured by X-ray diffraction (XRD) and X-ray fluorescence (XRF) spectroscopy. XRD results showed that the synthesized samples exhibited an orthorhombic structure of LaFeO3 and a hexagonal wurtzite structure of ZnO. However, the ZnO hexagonal wurtzite structure could not be detected below the ZnO molar ratio of 0.5. The presence of ZnO on the nanocomposites was confirmed using XRF measurements. The results revealed that the XRF spectra of the samples consisted of La, Fe, and Zn atoms. The photodegradation of methylene blue (MB) using LaFeO3/ZnO nanocomposites was then monitored under visible and UV light irradiation. The photodegradation results showed that the presence of LaFeO3/ZnO nanocomposites could degrade the MB solution. The highest MB degradation was found in the presence of ZnO at a molar ratio of 0.5. All of the LaFeO3/ZnO nanocomposites showed better photocatalytic performance than did LaFeO3 nanoparticles alone. Furthermore, several parameters, such as the effect of catalyst dose, initial concentration of MB, and various radical scavengers, were also measured to obtain the maximum condition and the main active species involved in the photocatalytic process.