Preparation, characterization of Fe, Ce Co-doped flower-like TiO2 photocatalysts and their properties in photocatalytic oxidation of arsenite

Abstract

Preoxidation process is usually needed in the treatment of arsenic containing water because arsenite (i.e., As(III)) is less easily to be removed by adsorption. Nano-scale titanium dioxide (TiO2) is an efficient photocatalyst for arsenite oxidation. In this study, a series of photocatalysts of un-doped, single-doped and co-doped flower-like TiO₂ were successfully prepared by template method using Fe(NO₃)₃ · 9H₂O, ammonium ceric nitrate and tetrabutyl titanate (Ti(OC₄H₉)₄) as precursors and glucan as template. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and N₂ adsorption-desorption measurement were employed to characterize the morphology, crystal structure and surface structure of the samples. The photoabsorbance of the obtained catalysts was measured by UV–Vis absorption spectroscopy, and the photocatalytic activities of the prepared samples under UV light were estimated by measuring the oxidation rate of As(III) in an aqueous solution. The characterizations indicated that the prepared photocatalysts had flowerlike structures, consisted of anatase phase and possessed high surface area of ca. 160 m²/g. It was shown that the Fe, Ce co-doped flower-like TiO₂ could be used as an effective catalyst in photocatalytic oxidation reactions. The synergistic effect of Fe and Ce co-doping played an important role in improving the photocatalytic activity. In addition, the possibility of cyclic usage of the co-doped flower-like TiO₂ was also confirmed, the photocatalytic activity of flower-like TiO₂ remained 88% of that of the fresh sample after being used four times.