Origin of the synergistic effect between TiO2 crystalline phases in the Ni/TiO2-catalyzed CO2 methanation reaction

The catalytic performances of TiO2-supported Ni catalysts for the methanation CO2 have been investigated using different crystalline phases TiO2 (rutile and anatase). activity depends appreciably on nature support. rate hydrogenation decreases in order 10Ni/TiO2-rutile ≫ 10Ni/TiO2-anatase. use a mixture containing 70% 10Ni/TiO2-anatase + 30% allows significant increase reaction related to 100% 10Ni/TiO2-rutile. Importantly, it has demonstrated that two do not need be direct contact synergetic effect occur. DRIFTS operando analysis during shows adsorbed CO accumulates Ni/TiO2-anatase Ni/TiO2-rutile, role Ni/TiO2-rutile is assist this Ni/TiO2-anatase. Increased also observed by adding Ni-free TiO2-anatase 10Ni/TiO2-rutile, indicating COx can occur bare if activated hydrogen supplied another source. H2-TPD analyses tests performed after dilution shown spillover (mediated surface or gas-phase species) at origin synergy between Sabatier reaction.