Properties and Potential Applications of Manganese-doped Ceria Gained by Mechanochemical Synthesis

摘要

Manganese doped nanosized ceria samples were prepared by mechanochemical synthesis.Characterization was done using X-ray diffraction(XRD),UV-Vis diffuse reflectance spectroscopy(UV-Vis DRS),X-ray photoelectron spectroscopy(XPS)and others.Different conditions of synthesis were tried.Beside cerium carbonate,cerium chloride and amorphous phase remain in the product.Cerium carbonate decomposes around 250℃,while the decomposition process centered at 330℃ was attributed to cerium chloride decomposition.Along with ceria,birnessite occurs in doped samples after thermal treatment and washing.Ceria lattice constant is reduced from 5.405 A for pure sample to 5.401 A for the 30% doped sample as a consequence of manganese entrance in the ceria lattice.Ceria bandgap is significantly reduced with doping.Particle size was far greater than crystallite size due to a strong tendency toward agglomeration.All prepared powders proved to be efficient catalysts for toluene oxidation with the 30% doped sample being the most promising.