Eu3+ doping-promoted Ni-CeO2 interaction for efficient low-temperature CO2 methanation

Abstract

CO2 methanation is gaining renewed attention due to the emerging application needs such as the power-to-gas concept and long-term space exploration missions. Maximizing the amounts of interfacial sites generally regarded as the efficient active sites is considered to be one of the most direct means to enhance catalytic activity but few breakthroughs have been made. Here, Eu3+ is introduced to Ni/CeO2 to promote the Ni-CeO2 interaction, resulting in a remarkable low-temperature CO2 methanation activity. Structural characterization indicates that the Ni/CeEu(9:1) catalyst achieves higher Ni dispersion compared to Ni/CeO2, which consequently generates more interfacial sites. More interfacial sites enhance the proportions of bidentate carbonates closer to interfacial sites as a faster hydrogenated species during the catalytic process, leading to enhanced low-temperature CO2 methanation activity over the Ni/CeEu(9:1) catalyst. This work provides a chemical strategy to enhance the amounts of active sites and bring insights into the origin of enhanced catalytic performance.