Optimization of nickel and ceria catalyst content for synthetic natural gas production through CO2 methanation

Abstract

Manufacturing of catalysts with high reaction rates at mild conditions is important for an efficient production of synthetic natural gas through the CO2 methanation process. In this work, the design of a technical catalyst based on an optimal content of Ni as active phase, CeO2 as promoter and γ-Al2O3 micro-spheres as support (dp = 400–500 μm) is evaluated. The systematic optimization of Ni, CeO2 and γ-Al2O3 content revealed that a proper balance of the positive effects that each component provided individually, was found at 25 wt% Ni, 20 wt% CeO2 and 55 wt% γ-Al2O3 content. This catalyst was stable for 120 h at 300 °C. The high loading of CeO2 is far from the classical definition of promoter and it covers the gap between the addition in a low amount as promoter and its uncompetitive use as bulk support. The highest catalytic activity was attributed to high metallic surface area (5 m2·g−1), high nickel reducibility (79% at 500 °C) and the formation of moderate basic sites that can adsorb CO2 (−65 kJ·molCO2−1). In comparison with similar research catalysts and a commercial reference, the optimum formation showed higher activity for synthetic natural gas production. Therefore, the micro-catalyst can be implemented in the micro-structured reactors that are available in the market.