Zr promotion effect in CO2 methanation over ceria supported nickel catalysts

Abstract

Carbon dioxide methanation is an interesting way to reduce greenhouse effect gases emission and, simultaneously, provide a renewable energy source of methane. Ceria and 15 at.% Zr-doped ceria supported nickel catalysts were characterized by means of various techniques (BET, XRD, Raman, H2-TPR, CO2-TPD, O2-TPO, OSC and H2-chemisorption) and evaluated in carbon dioxide methanation. Zr incorporation into catalyst formulation reduced catalyst's basicity but favored its reducibility, nickel availability and oxygen storage capacity. These characteristics gave rise to an improved catalytic performance both in terms of activity and stability: temperature required to achieve 50% conversion was reduced in 20 °C and low temperature (250 °C) stability was improved in around 8%. Initial rates approach was employed to determine reaction rates and apparent activation energies for CO2 methanation, which resulted in 113 and 121 kJ mol−1for Ni/CeO2 and Ni/Ce0.85Zr0.15O2, respectively.