Photodegradation of methyl violet 6B and methylene blue using tin-oxide nanoparticles (synthesized via a green route)

• A fast, facile, green method was developed for the synthesis of SnO2 NPs using water and glycerol.
• This method results in the formation of spherical SnO2 NPs of 8–30 nm within 5 min.
• The sizes of SnO2 NPs can be tuned by controlling the volume of glycerol, which acts as a good complexing and capping agent.
• The optical band gap energy of synthesized SnO2 NPs showed a clear blue shift from 3.78–4.17 eV with a decrease in grain size.
• SnO2 NPs act as an efficient photocatalyst in the degradation of methylene blue and methyl violet 6B, under direct sunlight.

Green synthesis of tin dioxide nanoparticles were developed by microwave heating method using 1:1, 1:2 and 1:3 volumetric ratio of water and glycerol, wherein glycerol acts as a good complexing as well as capping agent. This method resulted in the formation of spherical SnO2 nanoparticles with an average diameter ∼8–30 nm. The synthesized SnO2 NPs were characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED) and Fourier transformed infrared spectroscopy (FT-IR). The optical properties were investigated using UV–vis spectroscopy. The photocatalytic activity of synthesized SnO2 NPs was evaluated for the degradation of two different toxic dyes namely, Methyl Violet 6B and Methylene blue dye under direct sunlight.