Synergistic Effects of Ni-Co Alloy Active Sites and Promoter Modification on Nickel-Based Catalysts for Enhanced Performance in Dry Reforming Reactions

Dry reforming of methane (DRM) enables the simultaneous conversion of CH4 and CO2, yet rapid coking severely restricts the stability of Ni-based catalysts. In this study, Co was incorporated into Ce-, La-, and Zr-promoted Ni catalysts to construct Ni-Co alloy active sites, and their catalytic behavior was systematically evaluated. While single-promoter modification partially suppressed coke deposition at the expense of activity, Ni-Co alloy formation maintained high reforming performance and significantly enhanced stable catalytic performance within the 20 h evaluation period, with the Ce-promoted Ni-Co catalyst exhibiting the most durable anti-coking performance. CO2-TPD and coke characterization results indicate that promoter species enhance medium-strength basicity and oxygen mobility, thereby facilitating CO2 adsorption and accelerating the oxidation of surface coke intermediates; in particular, Ce supplies mobile active oxygen species through its oxygen storage-release capacity. DFT calculations further reveal that Co incorporation modulates the electronic structure of Ni sites, optimizing the balance between CH4 dissociation and CO2 activation and thus suppressing excessive methane cracking. These findings elucidate the synergistic effect of Ni-Co alloying and promoter modification in DRM and provide mechanistic insight for the rational design of coke-resistant Ni-based catalysts.