CO2 methanation over nickel‐based catalysts prepared by citric acid complexation method

Abstract

Catalytic hydrogenation of carbon dioxide to methane can not only achieve the recycling of carbon resources, but also effectively meet the increasing demand for natural gas. In this paper, Ni‐based catalysts on different supports including ZrO2, CeO2 and Al2O3 were synthesized using citric acid complexation method and their CO2 methanation performances were tested. Among these catalysts, the Ni/ZrO2 catalyst achieved the best CO2 methanation activity. The catalysts were characterized by N2‐physisorption, XRD, H2‐TPR and H2‐TPD. The results indicate that the superiority of the Ni/ZrO2 catalyst can be mainly ascribed to its not only high Ni dispersion but also high reduction degree. Since the reduction degree of Ni/Al2O3 is low, it exhibits poor activity. The preparation condition for the Ni/ZrO2 catalyst was further optimized. The result shows that at molar ratio of citric acid to Ni ions of 3, the catalyst exhibits the best activity owing to the highest Ni dispersion, the largest Ni surface area, an appropriate metal‐support interaction and the most moderate basic sites.