Promoted nickel-based catalysts on modified mesoporous silica support: The role of yttria and magnesia on CO2 methanation

In this research, a group of xY(2)O(3)-Ni/MgO-MCM-41 catalysts were synthesized by using direct synthesis method for CO2 hydrogenation and were characterized by employing BET, XRD, HRTEM, XPS, TPD, FE-SEM and TPO to understand the mechanism of CO2 hydrogenation over yttria-Ni/MgO-MCM-41. Compared to Ni/MgO-MCM-41, all catalysts which contained Yttria showed improved catalytic activity. The one with 2 wt% yttria had the highest catalytic performance, with carbon dioxide conversion and methane selectivity of 65.55% and 84.44% at 673 K, respectively, and high stability after 30 h. The impact of adding yttria, as a promoter, on nickel dispersion and that of enhancing carbon dioxide adsorption sites on basicity sites attracted more attention as effective factors regarding conversion, selectivity, and stability.