Performance of Cerium Oxides from Different Preparation Methods for Desulfurizing Hot Coal Gas

Four CeO₂ samples were prepared by pyrolysis of cerium hydroxide, cerium nitrate, cerium oxalate, and cerium perchlorate. The structures of CeO₂ samples were characterized by means of X-ray diffraction and nitrogen adsorption-desorption. Temperature-programmed reduction and thermogravimetry tests were carried out to evaluate the reduction and sulfurization behaviors of the CeO₂ samples. The results indicate that the samples, prepared from different precursors, have larger surface areas and pore specific volumes, smaller average crystallite sizes, and better reducibilities (except the sample from cerium perchlorate) than the CeO₂ reagent. The sulfurization performances of CeO₂ samples are directly correlated with the reduction degrees of CeO₂ samples. Compared with fresh CeO₂ samples, reduced ones have better sulfurization performances. Among the four CeO₂ samples, the one prepared from cerium nitrate, with the best reducibility, exhibits the best performance in sulfurization.