Boosted Effect of Carbon Atoms in Bifunctional Ni Catalysts for Dry Reforming of Methane at Low Temperatures

Deactivation from coke deposition on Ni catalysts in the dry reforming of methane (DRM) remains an intractable problem at low temperatures, particularly for biogas with a high CH 4 /CO 2 ratio often above 1. Herein, we engineer a bifunctional catalyst composed of a Ni 3 ZnC 0.7 core for CH 4 activation and an external CaO promoter with high dispersion for CO 2 capture and activation. Remarkably, the optimal catalyst exhibits outstanding activation capability through the in situ -induced formation of the Ni 3 ZnC 0.7 structure, enabling low-temperature H 3 C–H bond cleavage, while CaCO 3 intermediates synergistically enhanced methane activation kinetics. The optimized system achieved CH 4 and CO 2 conversions of 47.7 and 71.6% with a H 2 /CO ratio of 1.02 at 600 °C in CH 4 -rich DRM. Notably, the system maintained thermodynamic control over H 2 /CO ratios above 550 °C, effectively inhibiting the reverse water–gas shift reaction. This atomic- to system-level design establishes a paradigm for stable DRM catalysis without energy-intensive pretreatment.