Visible-light assisted methylene blue and methyl orange degradation using SnO micro sheets: Mechanistic insight and degradation pathways

Abstract

The hydrothermal method is used to synthesize the various morphologies of stannous oxide (SnO) for photocatalytic degradation under visible light irradiation. The catalytic activities of SnO samples were investigated for the degradation of the methylene blue (MB), and methyl orange (MO) dyes. The prepared SnO samples were characterized by the X-ray diffraction (XRD) technique, field emission scanning electron microscopy (FESEM), UV–visible spectroscopy, and Brunauer-Emmett-Teller (BET) technique. The UV–visible spectroscopy monitored the proportion of the dyes in an aqueous solution. The synthesized SnO sample D exhibit excellent activity with degradation efficiencies of >79 % and >96 %, respectively for MO and MB dyes, up to 120 min of irradiation to a visible light source. BET analysis further confirmed that sample D is a mesoporous material with a 55.354 m²/g specific surface area and an average pore diameter of 12.546 nm. The catalytic activity of MO and MB dyes with SnO samples was analyzed under pseudo-first-order conditions. The most effective catalyst, sample D, exhibited good performance during the reusability analysis, reaching an activity of 66 % and 85 % up to the fifth analyzed cycle of reuse SnO sample D for MO and MB dyes.