RESUMO
The reforming of methane from biogas has been proposed as a promising method of CO2 utilization. Co-based catalysts are promising candidates for dry methane reforming. However, the main constraints limiting the large-scale use of Co-based catalysts are deactivation through carbon deposition (coking) and sintering due to weak metal-support interaction. We studied the structure-function properties and catalytic behavior of Co/TiO2 and Co-Ru/TiO2 catalysts using two different types of TiO2 supports, commercial TiO2 and faceted non-stoichiometric rutile TiO2 crystals (TiO2 *). The Co and Ru metal particles were deposited on TiO2 supports using a wet-impregnation method with the percentage weight loading of Co and Ru of 5% and 0.5%, respectively. The materials were characterized using SEM, STEM-HAADF, XRD, XPS and BET. The catalytic performance was studied using the CH4 : CO2 ratio of 3 : 2 to mimic the methane-rich biogas composition. Our results indicate that the addition of Ru to Co catalysts supported on TiO2 * reduces carbon deposition and influences oxygen mobility. Co and Co-Ru catalysts supported on TiO2 * has superior activity with the highest conversion of CO2 and CH4 of 34.7% and 23.5%, respectively. Despite the improved performance, the Co-Ru/TiO2 * catalyst has limited stability due to the proliferation of nanoparticle growth and TiOx layers on the surface of the nanoparticles indicating the prevalence of the strong-metal support interaction.
