Soft-chemistry routes were used to synthesize Ce0.9Gd0.1O1.95 (CGO) membrane materials with attractive structural, morphological and textural properties. In the intermediate temperature domain between 500 C and 700 C, the average crystallite size is in the range 8-22 nm and the specific surface area varies from 43.4 m(2)/g to 8 m(2)/g. The corresponding supported membranes were synthesized by an infiltration method on/in alpha-Al2O3 tubular supports. The specific surface area of the CGO supported membrane reaches 18.5 m(2)/g at 700degreesC, i.e. a higher value than for powders. The gas permeation properties of the membranes were studied up to 500degreesC. A dispersion of Pt nanoparticles within the membrane material has been also investigated in order to study the role of noble metals in the oxygen transfer from the gas phase to the ceria crystallites (solid/gas interface). Post-impregnation of Pt revealed an adapted synthesis method to enhance surface oxygen transport for the CGO material.