Combination of sunlight, oxidants, and Ce-doped TiO2 for phenol degradation.

The degradation of phenol was used as a model reaction to investigate the photocatalytic properties of cerium-doped (0.1 nominal atomic percent) TiO2 catalysts in the presence and in the absence of oxidants: persulfate (PS) or hydrogen peroxide (HP). Experiments were performed in batch reactors using either artificial light (ultraviolet or visible) or solar exposure during spring-summer seasons in La Plata City (34.90° S, 57.92° W, 15 MASL). The formation of hydroquinone, catechol, and p-benzoquinone was observed in all the experiments. Additionally, for the experiments with PS (with or without catalyst), evidence of the formation of dimers and trimers was found. Total degradation of phenol (250 μM) was achieved with doped material and 7 mM of PS (two doses) after 3 h of solar exposure (H SUV, T  = 2.9 ± 0.6 105 J m-2).