Enhanced low-temperature dry reforming of methane over morphology-controlled Co/CeO2 catalysts: the critical role of oxygen vacancies and Co–O–Ce interfaces

Dry reforming of methane (DRM) is a promising route for the simultaneous utilization of CH 4 and CO 2 to produce syngas, yet the development of efficient and stable catalysts for low-temperature DRM remains highly challenging. In this work, a series of Co/CeO 2 catalysts with morphology-controlled ceria supports were prepared to investigate the structure–performance relationship in DRM. Among them, the catalyst supported on CeO 2 nanorods (Co/CeO 2 -R) exhibited the best catalytic activity and stability at 600 °C. Structural characterization suggests that the CeO 2 -R support provides a higher surface area and defect density, which favors Co dispersion and the formation of Co-O-Ce interfacial structures. Raman, XPS, and H 2 -TPR results indicate that Co/CeO 2 -R possesses a higher concentration of oxygen vacancies and stronger interfacial interactions compared with other catalysts. CO 2 -TPD measurements further show enhanced CO 2 adsorption capacity, which is consistent with the increased density of defect sites. The results collectively suggest that the improved catalytic performance originates from the synergistic effect of Co dispersion, oxygen vacancies, and Co-O-Ce interfacial structures, which together promote CO 2 activation, oxygen transfer, and carbon removal. In situ DRIFTS results suggest a bifunctional reaction pathway, in which CH 4 activation is likely to occur on Co sites, while CO 2 is activated on defect-rich CeO 2 surfaces to form carbonate/formate species that may participate in carbon removal. Overall, this work establishes a structure-performance correlation between CeO 2 morphology and catalytic behavior, providing insights into the design of Co-based catalysts for low-temperature DRM.