Enhanced removal of Rhodamine B from aqueous solution using a novel generation photocatalyst based Sb doped SnO2 nanoparticles

Antimony-doped tin oxide (Sb doped SnO2) nanoparticles were synthesized via a hydrothermal method and evaluated as photocatalysts for the degradation of Rhodamine B (RhB) dye under UV light irradiation. A series of Sb doped SnO2nanostructures with varying Sb doping concentrations (0.1, 0.3, and 0.5 at.%) were synthesized and the effect of Sb incorporation on the structural, morphological, and photocatalytic properties of SnO2have been investigated. X-ray diffraction and transmission electron microscopy analyses confirmed the effective doping of Sb into the SnO2lattice without the formation of secondary phases. A systematic reduction in average particle size was observed with increasing Sb content: undoped SnO2nanoparticles exhibited an average particle size of 4.6 ± 0.9 nm, which decreased to 4.0 ± 0.9 nm, 3.7 ± 0.8 nm, and 3.1 ± 0.6 nm for 0.1, 0.3, and 0.5 at.% Sb doping levels, respectively. This size reduction is attributed to the inhibitory effect of Sb on crystal growth during precipitation. X-ray photoelectron spectroscopy analyses revealed the coexistence of Sb3+and Sb5+oxidation states and a significant increase in surface oxygen vacancies, particularly at 0.3 at.% Sb doping level. Photocatalytic performance tests demonstrated that all Sb doped SnO2samples exhibited enhanced RhB degradation efficiency compared to undoped SnO2. Notably, the 0.3 at.% Sb doped SnO2sample achieved 99.1 ± 0.2 % RhB removal within just 30 min and reached 99.9 ± 0.1 % after 90 min of UV irradiation. Kinetic studies showed that the degradation followed a pseudo-first-order model, with the highest apparent rate constant (kapp = 0.0537 ± 0.001 min−1) observed for the 0.3 at.% doped sample. Furthermore, this optimized catalyst exhibited excellent recyclability, maintaining 84 % of its degradation efficiency after five consecutive cycles. These results suggest that Sb doping, particularly at an optimal concentration of 0.3 at.%, effectively enhances the photocatalytic activity by tuning its particle size, electronic structure, and surface chemistry, making it a promising candidate for wastewater treatment applications.