Photocatalytic degradation of methylene blue dye under direct sunlight irradiation using SnO2 nanoparticles

Abstract

• SnO 2 has been successfully synthesized using hydrothermal method. • Methylene blue was efficiently degraded by SnO 2 NPs under sunlight irradiation. • Catalyst dose and dye initial concentration significantly affected the rate of MB decomposition. • The rate of MB degradation was enhanced in the presence of H 2 O 2 oxidant. In this work, we report the hydrothermal synthesis, characterization, and photocatalytic activity of SnO 2 nanoparticles (NPs) towards methylene blue (MB) dye. The synthesized sample was characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), ultraviolet–visible (UV–Vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N 2 -sorption isotherm techniques. Results show that synthesized sample was tetragonal structure with an optical bandgap, average crystallite size, and degree of crystallinity equal to 3.67 eV, 21 nm, and 70%, respectively. The impacts of dye initial concentration, catalyst dose, and oxidant addition on the sunlight-assisted photodegradation performance were investigated. Degradation of 97% was achieved in 2 h of irradiation utilizing 10 ppm dye initial concentration and 40 mg catalyst dose at natural pH and in the absence of any oxidant. However, in the presence of the H 2 O 2 oxidant complete removal was observed in just 90 min without changing other parameters.