Enhancing the Formation of C₂₊ Hydrocarbons in CO₂ Hydrogenation Through Co₂C/CeO_x Interactions

Cobalt carbide (Co₂C) shows promise for CO₂ hydrogenation to C₂₊ hydrocarbons via the CO₂-Fischer-Tropsch pathway, although the production rate is still limited by the slow CO hydrogenation step. Herein, we developed CeO_x-modified Co₂C catalysts. At a Co/Ce molar ratio of 99, the catalyst achieved a C₂₊ hydrocarbon space-time yield of 106 mmol g_cat ^-1 h^-1 at 35% CO₂ conversion (300°C, 3 MPa), outperforming all reported Co-based catalysts and comparable to some Fe-based catalysts. Characterizations and kinetic studies reveal that highly dispersed CeO_x interacts with Co, forming abundant and intimately contacted interfaces and effectively tuning the electronic structure of Co₂C. The Co₂C-CeO_x electronic interaction enhances CO adsorption and H₂ activation, accelerating the rate-determining CO hydrogenation and ultimately boosting C₂₊ hydrocarbon formation. This work provides a feasible strategy for designing efficient Co₂C-based catalysts for CO₂ hydrogenation.