Role of Cerium–Zirconium Ratio and Chemical Surface Property of CeO2–ZrO2 Supported Nickel-Based Catalysts in Dry Reforming Reaction

This study investigates the effect of cerium–zirconium supported nickel catalyst (Ni/CeZr(x)) on the dry reforming reaction of methane (CH4) and carbon dioxide (CO2) to produce hydrogen (H2) and carbon monoxide (CO) for use in petrochemical processes. CeZr supports were synthesized via template-assisted co-precipitation using CTAC as a template with varying pH values (5, 7, 8.5, and 10) and underwent hydrothermal processing. Nickel (10% by weight) was then loaded onto the support through incipient wetness impregnation. The dry reforming reaction was performed at 700 °C. Results revealed that as the pH increased from acidic to basic conditions, the precipitation and integration of ZrO2 and CeO2 improved, leading to the formation of CeZr(x) composite supports. The Ce/Zr ratio in Ni/CeZr(x) catalysts influenced the generation of oxygen vacancies (OV) on the catalyst surface, affecting CO2 and CH4 conversions and the H2/CO ratio. The Ni/CeZr(8.5) catalyst exhibited the highest activity and stability due to its high surface oxygen vacancy and the number of basic sites on the CeZr(8.5) surface. Moreover, this catalyst reduced coke formation by promoting CO2 adsorption and dissociation, which facilitated the formation of surface-bound oxygen species that reacted with the surface carbon species.