Cooperation Between Active Metal and Basic Support in Ni-Based Catalyst for Low-Temperature CO2 Methanation

Abstract

The key challenge for CO2 methanation, an eight-electron process under kinetic limitation, relies on the design of non-noble metal catalysts so as to achieve high activity at low reaction temperatures. In this work, four Ni-based catalysts with different supports were prepared and tested for CO2 methanation at 250–550 °C in a fixed bed quartz reactor and further characterized to reveal the structure–function relationship. The Ni-based catalysts followed an activity order of Ni/CeO2 > Ni/Al2O3 > Ni/TiO2 > Ni/ZrO2, especially at temperatures lower than 350 °C. H2-TPR and TPD results indicated that the interaction between nickel and support was strong and the metallic nickel was well dispersed in the Ni/Al2O3 catalyst, while more amount of CO2 was adsorbed on the weak basic sites in the Ni/CeO2 catalyst. By establishing the correlation between the catalytic performance and the catalyst structure, it was found that the Ni nanoparticles and basic support serve as H2 and CO2 active centers respectively and cooperatively catalyze CO2 methanation, resulting in high low-temperature reaction activity. High CO2 conversion was achieved over Ni/CeO2 catalyst at 300 °C for its high H2 uptake on Ni nanoparticles and high CO2 adsorption capacity on the support with weak basic sites and cooperatively to catalyze CO2 methanation.