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Catalysis Today, Vol.306, 300-309, 2018
Mesoporous cerium-doped titania for the photocatalytic removal of persistent dyes
Mesoporous titanium dioxide was prepared by Evaporation Induced Self Assembly (EISA) method from titanium isopropoxide as precursor, and cetyl-trimethyl-ammonium bromide as surfactant. This sample was doped with cerium oxide by incipient wetness impregnation (IWI), using cerium ammonium sulfate. Two other samples of mesoporous TiO2 doped with cerium oxide were prepared by EISA, using cerium ammonium sulfate and cerium nitrate as precursors. The samples were calcined at 773, 873 and 973 K to remove the templating surfactant. The powder XRD characterization indicated the formation of anatase structure for all the calcination temperatures. The investigation of the porous structure by pure nitrogen adsorption at 77 K (BET method) showed that the samples had specific surface areas between 25 and 190 m(2) g(-1) and free pore volumes of 0.15-0.35 cm(3) g(-1), depending strongly on the nature of the dopant and the preparation procedure. The band gap values of the materials deduced by UV-DR spectroscopy were situated between 2.35-2.93 eV. The photocatalytic tests indicated yields of up to 72% for Rhodamin 6G decolorization under UV irradiation. The photocatalytic performances of the different samples were correlated to the results of XPS spectra, the best behavior being due to the synergetic effect of Ce (III), Ce (IV) and O alpha species, involved in HO center dot radicals obtaining. (C) 2016 Elsevier B.V. All rights reserved.