The effect of the cerium precursor and the carbon surface chemistry on the dispersion of ceria on activated carbon

摘要

Activated carbon-supported cerium dioxide (CeO₂/C) was prepared by impregnation of a commercial support (Norit R2030) with aqueous solutions of two different cerium precursors, [(NH₄)₂Ce(NO₃)₆] and Ce(NO₃)₃·6H₂O. The effect of carbon surface chemistry on the dispersion of ceria was studied by using two different carbon supports, the R2030 and the same material after an oxidation treatment with H₂O₂. Thus, four samples were obtained by combining the precursors and the supports. The prepared materials were characterized by thermogravimetry, nitrogen adsorption isotherms (77 K), X-ray diffraction, temperature-programmed desorption, temperature-programmed reduction and transmission electron microscopy, in order to study the degree of ceria dispersion over the supports. It was found that the best results in terms of ceria dispersion were obtained for the material prepared with the oxidized carbon and ammonium cerium nitrate as cerium precursor.