SnO2–SrO based nanocomposites and their photocatalytic activity for the treatment of organic pollutants

• Synthesis of SnO2–SrO based nanocomposites using two different methods.
• Comparison of the particle size, nature and photocatalytic activity.
• Characterization on the basis of XRD, SEM, TEM and TGA analyses.
• Potential application for the photochemical degradation of environment pollutants.

The present paper reports development of SnO2–SrO based nanocomposites using facile hydrothermal and sol–gel method. Nanocomposites were characterized on the basis of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Studies (EDS), Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR), Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) techniques. The materials were explored for the photocatalytic activity regarding the treatment of organic pollutants viz-azo-dye, pesticide and drug. In addition, a comparative study was performed in term of particle size using hydrothermal and sol–gel route. It was observed that hydrothermal route showed an improved particle size, which affects the photocatalytic activity, porosity and crystalline nature of the nanocomposite. Further, kinetic and thermodynamic parameters were also calculated for the photodegradation experiments. It was found that the rate of photodegradation reaction followed the pseudo-first order kinetics and the highest rate was observed for azo-dye while it was lowest for the drug. A negative values of the Gibbs free energy (ΔG) show that the photodegradation proceeds with a net decrease in free energy of the system. The results of photodegradation of dye, pesticide and drug indicate that nanocomposites of SnO2–SrO can be effectively applied for the treatment of organic pollutants.