Investigations on the surface properties of pure and alkali or alkaline earth metal doped ceria

The effect of parameters, such as initial cerium concentration and alkali or alkaline earth concentration in the reactant solution on the properties of precipitated ceria, have been investigated by nitrogen adsorption isotherm analysis, FTIR spectroscopy and X-ray powder diffraction. Increasing cerium concentration in the reactant solution has a negative effect on the surface properties of ceria, especially on calcined samples. Addition of alkali ions leads to the gradual lessening of the specific surface area; the effect is strongly depended on the ionic potential of the guest alkali ion. Go-precipitation of magnesium and cerium leads to the formation of separate magnesia solid phases within the ceria mesopores resulting in an anomalous behaviour of the surface properties of ceria. Go-precipitation of calcium and cerium results in the formation of homogeneous Ca-Ce mixed oxides with surface properties depended on the calcium content of the mixed oxide. In contrast to co-precipitation, using the incipient wetness method leads to the formation of separate calcium oxide phase within the ceria mesopores.