Highly active Ni/CeO₂ catalyst for CO₂ methanation: Preparation and characterization

A Ni/CeO₂ catalyst was prepared via decomposition of nickel precursor by gas discharge plasma, followed by hydrogen reduction thermally. The activity of the obtained catalyst reaches the highest level towards CO₂ methanation with methane selectivity above 99 % at reaction temperatures lower than 300 °C. For example, the CH₄ formation rate at 275 °C is 100.3 μmol g_cat⁻¹ s⁻¹, higher than the reported catalysts at the same reaction temperature. Characterization results indicate that the plasma decomposition leads to an interfacial structure where Ni atoms bind with O atoms from ceria. A strong metal-support interaction is caused. Rich interfacial Ni-CeO₂ sites are thus formed with excellent redox property. The unique interfacial structure confines small nickel particles on the ceria surface, exposing more metallic Ni as active sites for splitting H₂. Therefore, the plasma prepared Ni/CeO₂ catalyst shows balanced active sites for H₂ splitting and CO₂ activation, improving low temperature catalytic activity significantly.