A comparative study of the effect of metal–support interaction on catalytic CO₂methanation over Ni/Ce_xZr_{1− x}O₂catalysts under thermal and plasma conditions

Metal–support interaction (MSI) is a well-established strategy for tuning catalytic activity in thermal catalysis, yet its role in nonthermal plasma catalytic CO₂ methanation remains insufficiently explored. In this study, Ni/Ce_xZr_1−xO₂ catalysts were synthesized using Ce_xZr_1−xO₂ supports calcined at different temperatures to systematically modulate the MSI. A volcano-shaped correlation was observed between the catalytic activity and support calcination temperature in both thermal and plasma systems. The Ce_xZr_1−xO₂ support calcined at 600 °C having a moderate particle size, demonstrated the optimum MSI (i.e., promoting the facile formation of oxygen vacancies and stable interfacial anchoring of Ni particles) and thus the comparatively best catalytic performance under both conditions. Under the tested conditions, thermal CO₂ methanation exhibited superior activity compared to plasma-assisted reactions, e.g., the NCZ-600 catalyst achieved an 83% CH₄ yield at 350 °C versus 11.3% at 7.0 kV. These results underscore the critical role of the MSI in governing CO₂ methanation across distinct catalytic environments and highlight its potential as a unifying design principle for both thermal and plasma catalysis.