Enhanced photocatalytic activity of Sn-doped TiO₂ nanoparticles: Microstructural-photoelectrochemical synergy

The material prepared by synthesizing titanium dioxide (TiO₂) powder via sol-gel refluxing using titanium tetraisopropoxide (TTIP) as a precursor was doped with varying concentrations of tin (Sn) at 0.25 %, 0.50 %, and 0.75 %. Characterization techniques including scanning electron microscopy (SEM) were employed to analyse particle sizes, revealing dimensions ranging between 12 and 20 nm. Subsequent X-ray diffraction (XRD) and Raman spectroscopy confirmed the formation of phase-pure nanocrystalline anatase, corroborated by Fourier transform infrared spectroscopy (FTIR) that identified Ti–O–Ti bonding in anatase titania. Surface area analysis using Brunauer-Emmett-Teller (BET) analysis showed a gradual increase in surface area with increasing Sn doping levels, from 100.5 m²/g for pure TiO₂ to 116.9 m²/g for 0.75 % Sn-doped TiO₂. UV–Vis spectroscopy demonstrated distinct absorption peaks and corresponding band gaps, with 0.75 % Sn-doped TiO₂ exhibiting the broadest absorption in the range of 400 –800 nm. Photocatalytic decomposition of methylene blue was then evaluated, revealing enhanced performance with Sn-doped titania, particularly with 0.75 % Sn doping, suggesting its superiority in organic pollutant degradation. This observation underscores the potential of Sn-doped TiO₂ as an effective photocatalyst.