Facile preparation of a Ni/MgAl2O4 catalyst with high surface area: Enhancement in activity and stability for CO methanation

Abstract

To enhance the performance of anti-coking and anti-sintering of the Ni-based catalysts during the reaction process of CO methanation, we synthesized a group of catalysts denoted as "Ni-xMgAl2O4" via the modified co-precipitation method utilizing carbon black as hard template. The addition of carbon black could significantly improve the specific surface area of MgAl2O4 to 235.8 m2 g-1. The Ni catalysts supported on high-surface-area MgAl2O4 (Ni-0.25MA) exhibited enhanced catalytic performance and hydrothermal stability in comparison with the conventional Ni-based magnesia alumina spinel catalysts with the same NiO content. In the process of 120-h stability test, the Ni-0.25MA catalyst exhibited remarkable improvement in both anti-sintering and anti-coking. After a series of characterizations, we found that the addition of carbon black could make more pores over MgAl2O4, resulting in the supported Ni particles being anchored in the pore rather than on the outside surface of support. This structure enhanced the dispersion of nickel nanoparticles, thus strengthening the interaction between nickel species and the MgAl2O4 support, which led to the promotion in catalytic activity and stability of high-surface-area Ni/MgAl2O4.