Tailored morphology of indium-doped titania via sol-gel method for enhanced photocatalysis

This study investigates the photocatalytic decomposition of methylene blue (MB) using indium-doped titania nanoparticles (TiO₂ NPs), synthesized via the sol-gel reflux method, and explores their potential in heterojunction photocatalysis. Titanium tetraisopropoxide was utilized as the precursor, with indium (In) incorporated in varying concentrations (0.25, 0.50, and 0.75 wt%) to enhance photocatalytic activity. Scanning electron microscopy and atomic force microscopy that revealed particle sizes ranging from 12 to 22 nm. X-ray diffraction and Raman spectroscopy confirmed the formation of phase-pure nanocrystalline anatase TiO₂. Fourier transform infrared spectroscopy verified the presence of Ti-O-Ti bonding characteristic of the anatase phase. Surface area analysis indicated an increase in surface area with indium doping, rising from 102.9982 m²/g (0.25 wt% In-doped) to 104.5035 m²/g (0.50 wt% In-doped) and reaching 109.8041 m²/g at the highest concentration. Optical properties revealed a corresponding decrease in bandgap energy, which dropped from 3.31 eV (pure TiO₂) to 2.97 eV (0.75 wt% In-doped). The results demonstrated that indium doping significantly enhanced the overall photocatalytic degradation of MB, 85 % degradation was achieved after 8 h of UV irradiation at 0.25 wt% In-doped TiO₂, making indium-doped titania a promising material for photocatalytic applications.