In this work, non-ordered and ordered CeO2-based catalysts are proposed for the CO2 conversion to dimethyl carbonate (DMC). Particularly, a non-ordered mesoporous CeO2, consisting of small nanoparticles of about 8 nm, is compared with two highly porous (635-722 m2/g) ordered CeO2@SBA-15 nanocomposites obtained by two different impregnation strategies (a two-solvent impregnation (TS) and a self-combustion (SC) method), with a final CeO2 loading of 10 wt%. The Rietveld analyses on XRD data combined with TEM imaging evidence the influence of the impregnation strategy on the dispersion of the active phase: nanoparticles of 8 nm for the TS composite vs. 3 nm for the SC composite. The catalytic results show comparable activity for the mesoporous ceria and the CeO2@SBA-15_SC nanocomposite, while a lower DMC yield was found for the CeO2@SBA-15_TS nanocomposite. This finding is presumably ascribed to a partial obstruction of the pores by the CeO2 nanoparticles in the case of the TS composite, which leads to a reduced accessibility of the active phase. On the other hand, in the case of the SC composite, where the CeO2 particle size is much lower than the pore size, there is an improved accessibility of the active phase to the molecules of the reactants.