Via integrative chemistry, the first CoOx–SiO2(HIPE) self-standing monoliths of cobalt nano-oxides embedded within silica macro–mesocellular hosts have been prepared. These binary CoOx–SiO2 porous nanostructure (MUB-100­(x)) materials 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 and 500 m2 g–1 when assessed by Ar physisorption 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 β-Co­(OH)2 phase coexisting with the silica network, whereas 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 considering 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% conversion for a light-off temperature (T 50) 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 performance and reaching thermodynamic stability from cycle 2 to cycle 4.

In the general context of environmental air remediation, copper-oxide-based self-standing porous catalysts (MUB-103(x)) and their reduced homologues (Red MUB-103(x)) have been synthesized and studied for the thermoconversion of CO to CO2. Catalytic experiments under dry air conditions reveal that for nonreduced catalysts, increasing the Cu content diminishes the light-off temperature T 50 (corresponding to 50% conversion). The catalytic performances exhibited by the CuO phase dispersed in the silica pores of MUB-103(x) samples are the highest reached to date despite the limitations of the experimental conditions used. After reduction with H2, the native Red MUB-103(x) catalysts offer CO conversion efficiencies significantly more increased, leading to a lowering of the T 50 values equal to at least 100°C. As such, the CO conversion reaches a T 50 value of 160 °C for Red MUB-103(2) with 1.81 wt % Cu; this catalyst displays a specific rate of 8.6 mmolCO gCu –1 s–1 at 175 °C, largely higher than those observed to date. The performances of the Red MUB-103(2) sample were evaluated for CO oxidation under humid conditions with the addition of 5 vol % water vapor in the feed during four cycles, leading to the same efficiency when compared with that under dry experimental conditions, revealing robustness. A drastic increase in the CO conversion temperature was observed for the 4th cycle, i.e., after 8 h under humid conditions. Analyses of the spent Red MUB-103(2) catalyst after four cycles reveal a slight oxidation of copper, leading to Cu2O species. Importantly, after four cycles, the deactivated catalyst was able to partially recover its performance when reactivated through a 2 h reducing treatment under H2 at 400 °C.