Through the integration of sol-gel chemistry, lyotrope mesophases and emulsions, the first CoOx-SiO2(HIPE) series of cobalt nano-oxides were embedded within silica macromesocellular self-standing hosts. These binary CoOx-SiO2 porous nanostructures (MUB-100(x)) series present an average of 95% porosity. We found out that high cobalt concentration maintains the hexagonal-2D organization of the mesoscopic voids when applying the thermal treatment at 700°C. Their specific surface areas fall between 400-500 m 2 g-1 when assessed from Ar physi-sorption measurements. At the microscopic length scale, as revealed through magnetic investigations, the low cobalt content foams MUB-100(1) and MUB-100(2) are made of the amorphous -Co(OH)2 phase coexisting with the silica network, while increasing the cobalt concentration during the one pot syntheses (MUB-100(3) and MUB-(4) materials) favors the formation of the spinel Co3O4 and olivine Co2SiO4 crystalline nanoparticles embedded within silica. When it turns towards the CO oxidation catalytic performance, the MUB-100(4) is able to totally convert the CO flow before 200°C (starting at 125°C) while achieving 50% of conversion for a light-off temperature T50 of 145°C, revealing the good efficiency of the MUB-100(4) in CO oxidation with which up to 4 catalytic cycles have been performed without disrupting drastically the catalytic performances while reaching thermodynamic stability from the cycle 2 to the cycle 4.< Leer menos