Ce-Doped SnO2 Nanoparticles for Efficient Photocatalytic Degradation of Organic Dyes and Antibiotics Under Sunlight Exposure.

Ce-doped SnO2 nanoparticles (CSNPs) were synthesized via a hydrothermal precipitation method followed by annealing at 600°C for 2 h under ambient conditions, and evaluated as sunlight-driven photocatalysts for the degradation of organic dyes and antibiotics. X-ray diffraction analysis confirmed the formation of a tetragonal rutile SnO2 crystal structure for all Ce concentrations, with no secondary phases detected. The CSNPs exhibited enhanced light absorption and favorable surface properties, thereby improving photocatalytic performance. Among the CSNPs, Ce = 5 at.% (CS5) showed the highest activity, achieving degradation efficiencies of ∼95.36% for crystal violet (CV), ∼93.39% for methylene blue (MB), ∼86.66% for methyl orange (MO), and ∼79.00% for ciprofloxacin (CPF) under natural sunlight irradiation. The enhanced activity of CSNPs is attributed to bandgap narrowing (3.50 → 3.35 eV), efficient charge separation, and the generation of reactive oxygen species (•O2 - and •OH). Radical-trapping experiments demonstrate the potential of CSNPs as a cost-effective photocatalyst for water purification.