Tuning Ni–Co Interactions on MgO–ZrO2-Modified Al2O3 for Balanced Activity and Stability in Dry Methane Reforming

This work investigates the effect of Co incorporation on the physicochemical properties and dry reforming of methane (DRM) performance of Ni catalysts supported on surface-modified γ-Al2O3 containing 9 wt% MgO and 1 wt% ZrO2 (MS). Bimetallic catalysts containing 5 and 10 wt% Co with a fixed Ni loading of 10 wt% were prepared by co-impregnation. H2-TPR and H2-TPD analyses revealed the Co incorporation reducibility and hydrogen adsorption–desorption characteristics of the catalysts. These changes were accompanied by enhanced DRM activity and increased H2/CO ratios, which may reflect changes in the contributions of competing reactions, including the reverse water–gas shift reaction. Although 10Ni10Co/MS exhibited the highest CH4 and CO2 consumption rates and H2/CO ratio, its enhanced activity was accompanied by more-pronounced graphitic carbon features and greater catalytic deactivation. In contrast, 10Ni5Co/MS maintained more stable catalytic performance while retaining improved reactant utilization and H2/CO ratio. These findings suggest that controlled Co incorporation provides a favorable balance between DRM activity and resistance to carbon-associated deactivation, with 5 wt% Co providing the best activity–stability balance among the investigated catalysts.