Catalytic performance of Pd/Co3O4 on SiC and ZrO2 open cell foams for the process intensification of methane combustion in lean conditions

Ceramic open cell foams (OCF) are characterized by lower pressure drop, high geometric surface area, and enhanced radial convection in comparison with monolith-type supports. In this work, silicon carbide (SiC) and zirconia (Zir) OCF with different pore per inch (ppi) density were coated with 200 mg of Co3O4 by solution combustion synthesis and doped with 3 wt % of Pd via wetness impregnation. Their catalytic activity was tested toward the lean oxidation of methane at different weight hourly space velocities. Zir OCF with 30 ppi exhibits the best catalytic activity for all reacting conditions, followed by Zir 45 ppi, SiC 45 ppi, and SiC 30 ppi. The better performance of Zir OCF was rationalized considering their lower volumetric heat exchange coefficients, which favor the reaction heat removal by convection via the flue gases. A 200 h stability test on the best structured catalyst demonstrated full methane conversion at a temperature below 400 °C. These results confirm the fundamental role of thermal conductivity of the structured catalysts’ support.