Low-temperature CO₂ methanation over Ni catalysts supported on nanocrystalline CeO₂ in an electric field

Nickel catalysts supported on nanocrystalline CeO₂ exhibit intriguing properties, including high Ni dispersion, a high concentration of lattice oxygen defects in the support, and facile formation of hydroxyl groups on the Ni surface. In an electric field, CO₂ methanation was carried out using a Ni/CeO₂ catalyst. The reaction occurred even at around 393 K, a low temperature at which no activity was observed under conventional thermal conditions. In the CO₂ methanation environment, the amount of surface OH groups increased when an electric field was applied. Furthermore, adsorption species like hydroxy carbonyl, which were not detectable without the electric field, were identified. These findings suggest that applying an electric field influences the interface between Ni nanoparticles and CeO₂ particles, promoting the formation of oxygen vacancies and OH species on the Ni/CeO₂ catalyst. This enhances CO₂ activation, allowing the reaction to proceed at lower temperatures.