Optimization of an Open-Cell Foam-Based Ni-Mg-Al Catalyst for Enhanced CO₂ Hydrogenation to Methane

In the presented work, the catalytic performance of a nickel catalyst, in CO2 hydrogenation to methane, within a ZrO2 open-cell foam (OCF)-based catalyst was studied. Two series of analogous samples were prepared and coated with 100-150 mg of a Mg-Al oxide interface to stabilize the formation of well-dispersed Ni crystallites, with 10-15 wt% of nickel as an active phase, based on 30 ppi foam or 45 ppi foam. The main factor influencing catalytic performance was the geometric parameters of the applied foams. The series of catalysts based on 30 ppi OCF showed CO2 conversion in the range of 30-50% at 300 degrees C, while those based on 45 ppi OCF resulted in a significantly enhancement of the catalytic activity: 90-92% CO2 conversion under the same experimental conditions. Calculations of the internal and external mass transfer limitations were performed. The observed difference in the catalytic activity was primarily related to the radial transport inside the pores, confirmed with the explicitly higher conversions.