CO2 METHANATION OVER BIMETALLIC NICKEL-NOBLE METAL CATALYSTS

The CO2 methanation reaction was investigated over bimetallic Ni-NM catalysts supported on Pr-doped CeO2, where NM represents a noble metal (NM = Ru, Pt, Rh, Pd and Ir). 10% Ni and 1% NM were loaded over a mesoporous PrCeO2 support via co-impregnation and directly reduced at 400oC, without prior calcination. The prepared catalysts were characterized via XRD, N2-physisorption and HAADF-STEM along with EDS mapping. The addition of 1% Ru and Rh was shown to improve the dispersion of the metallic Ni phase and reduce pore blockage upon impregnation. Catalytic activity evaluation revealed that the addition of 1% Ru led to a remarkable increase in the catalytic activity, especially at lower temperatures. Pt and Ir addition led to minor changes in activity, whereas Rh and Pd incorporation surprisingly reduced CO2 conversion. The most active 1% Ru, 10% Ni/Pr-CeO2 catalyst was shown to be particularly stable over a 50h time-on-stream experiment at 325oC, with CO2 conversion and CH4 selectivity values at 80% and 99.5% respectively.