Photodegradation activity of yttrium-doped SnO2 nanoparticles against methylene blue dye and antibacterial effects

This review reports the effects of yttrium (Y) on the physicochemical characteristics of tin(II) dioxide (SnO2) nanoparticles (NPs), which were efficiently synthesized via a simple hydrothermal chemical route with different doping concentrations (0, 2 and 4 at%) of Y. The structural, optical and photocatalytic properties of the as-prepared Y-doped SnO2 (Y:SnO2) NPs were investigated, and the results are described. X-ray diffraction (XRD) studies showed that the undoped and Y:SnO2 NPs had a fine crystalline texture with a tetragonal structure and particle size range of 27–15 nm, although the size decreased with Y doping. High-resolution scanning electron microscopy (HRSEM) morphological analysis revealed spherical NPs forming agglomerates. Optical absorption was investigated by UV-visible diffuse reflectance spectroscopy, and showed a redshift in bandgap energy for Y3+-doped SnO2 NPs, and photoluminescence spectroscopy revealed the most intense emission peaks in the visible light region. Enhanced photocatalytic activity was observed for the doped samples, and the 4% Y:SnO2 NPs exhibited excellent photodegradation of methylene blue aqueous (MB) dye in visible light, demonstrating 92.34% degradation in 180 min. The other photocatalysts also demonstrated greater than 85% photodegradation efficiency and high stability, with no significant reduction in activity observed after five cycles. The results indicate that the superoxide (·O2−) radical, a key reactive species, played a vital role in the degradation of aqueous MB dye. The probable photocatalytic mechanism of the Y:SnO2 NPs was thoroughly investigated.