Cerium-Based Bimetallic Oxides as Catalysts for the Methanation of CO₂: Influence of the Preparation Method

Cerium-based bimetallic oxides of the type 3NiO·CeO2, Co3O4·CeO2, and 1.5Fe2O3·CeO2 were prepared by two sol–gel methods (epoxide addition and Pechini methods) and by the electrospinning technique, aiming at the synthesis of compounds with different morphologies (nanoparticles or nanofibers) and the evaluation as catalysts for the methanation of CO2. The results obtained show a catalytic performance that depends on the type of d block element, method, and catalyst morphology. Regardless of such parameters, the best results were those obtained over the nickel-based catalysts prepared by the electrospinning technique that are remarkably more active than a commercial rhodium catalyst used as a reference and tested in the same conditions. Moreover, the cobalt-based catalysts obtained either as nanoparticles (Pechini method) or fibers (electrospinning technique) present also a good activity, comparable to that measured over the reference catalyst. All catalysts were very stable to deactivation during at least 60–70 h of reaction, which is clearly an advantage that could make them an alternative to be considered for future developments in this area of knowledge.