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Lanthanum (La)-doped tin dioxide (SnO) nanoparticles were synthesized by a modified sol-gel method at room temperature. The samples were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The photocatalytic activity of La:SnO samples were investigated by studying the degradation profile of phenol and its by-products in water. The treated samples were analyzed by HPLC-UV and a UV-Vis spectrophotometer. Benzoquinone, catechol, resorcinol, hydroquinone, acetic acid, and 2-propanol were identified as phenol degradation intermediates. Maximum concentration acquired was in the order of catechol, resorcinol, hydroquinone, and benzoquinone, which was observed in the beginning stages while iso-propanol and acetic acid were observed in the final stages of phenol degradation. We achieved a complete photodegradation of a 10 ppm aqueous phenol solution and intermediates with 0.6 % of SnO:La nanoparticles in 120 min under artificial solar irradiation. A maximum degradation rate constant of 0.02228 min of propanol and a minimum of acetic acid 0.013412 min were recorded at 37 °C. [ABSTRACT FROM AUTHOR]

The influence of heterogeneous semiconductors on the photodegradation of phenol in water was investigated using doped tin dioxide (SnO) nanoparticles. Photocatalysts of SnO were synthesized with lanthanum (La), cerium (Ce), and neodymium (Nd) dopants. These photocatalysts were synthesized from tin tetrachloride by sol-gel method with different dopant concentrations, and its photocatalytic degradation was investigated up to 0.8 % under UV-A light in aqueous suspensions. The photocatalytic oxidation reactions were studied by varying photocatalyst composition, light intensity, reaction time, pH of the reaction medium, and phenol concentration. It was found that the photocatalytic activity of rare earth-doped SnO for phenol decomposition under UV light irradiation was considerably higher than that of pure SnO nanoparticles. The experimental results also indicate that more than 95 % phenol was effectively oxidized in the presence of an aqueous suspension of La: SnO nanoparticles within 120 min of UV light irradiation. [ABSTRACT FROM AUTHOR]