Synergistic effect of Ce–Mg promoted Ni catalysts on 3D structured open cell foams for CO2 hydrogenation to methane

Abstract

The macroporous 3D architecture of the open-cell foams enables superior heat and mass transfer, exceptional thermal conductivity, rapid heat dissipation, and minimal diffusion resistance, ensuring structural stability under the highly exothermic methanation conditions. Herein, this work investigates and compares the performance of ZrO₂-based 3D structured foams for thermocatalytic conversion of CO₂ to methane with excellent selectivity. The foams were coated using the solution combustion method, where initially 40 wt% Ce and (5–15 wt%) Mg were coated, and a further 30 wt% nickel was utilized for coating. The catalyst was characterized via PXRD, SEM, H₂-TPR, and CO₂-TPD, and FE-SEM, EDX analysis confirmed the presence of Ce, Mg, Ni, and O. The catalyst showed 78% conversion with ∼99% selectivity at 300 °C, whereas foams without using Mg promoter showed only 17% conversion with 90% selectivity towards methane. This result confirmed the synergistic effect between the Ce–Mg for the CO₂ methanation reaction and can be linked with the basicity of the Ni/Ce–Mg catalyst. Overall, this work contributes to CO₂ valorization and methane production with excellent selectivity and an easy synthesis process.