Clay exfoliation method as a route to obtain mesoporous catalysts for CO₂ methanation

A unique method for obtaining a mesoporous catalytic support through the exfoliation of a montmorillonite is reported. This method consisted of the intercalation of Na-clay with Al-Keggin species and polyvinyl alcohol followed by microwave irradiation. The mesoporous support was employed to prepare Ni-catalysts which were used in the natural gas synthesis through CO₂ methanation. The synthesis method was validated confirming the clay exfoliation and the main formation of mesopores. Also, the Ni-catalysts have mainly weak basic surface properties lower than 38 µmol.g^-1, and containing Ni⁰ nanoparticles with sizes between 9 and 12 nm which were thermally stable after reduction and methanation reaction. The catalyst with 5% Ni wt. gave conversions between 50 and 80% with temperatures ranging from 200 to 300 °C and selectivities of 100% towards the formation of CH₄ without coke formation. The (3 and 5% Ni) Ni-catalysts are stable up to 8 h at 400 °C in the methanation reaction maintaining 100% of selectivity.•Mesoporous catalytic supports are obtained through a unique clay exfoliation method (Al-keggin, PVA, and microwaves).•(3% and 5% wt.) Ni-mesoporous catalysts are thermally stable and Ni⁰ nanoparticles between 9 and 12 nm are achieved.•5%wt. Ni-catalyst have no deactivation up to 8 h at 400 °C and displays unprecedented performance at low temperatures in CO₂-methanation with 100% of selectivity.