CO 2 methanation over nickel‐based catalysts prepared by citric acid complexation method

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 ZrO 2 , CeO 2 and Al 2 O 3 were synthesized using citric acid complexation method and their CO 2 methanation performances were tested. Among these catalysts, the Ni/ZrO 2 catalyst achieved the best CO 2 methanation activity. The catalysts were characterized by N 2 ‐physisorption, XRD, H 2 ‐TPR and H 2 ‐TPD. The results indicate that the superiority of the Ni/ZrO 2 catalyst can be mainly ascribed to its not only high Ni dispersion but also high reduction degree. Since the reduction degree of Ni/Al 2 O 3 is low, it exhibits poor activity. The preparation condition for the Ni/ZrO 2 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.