Ni-based catalysts prepared by impregnation combustion method for CO methanation in a slurry-bed reactor

A series of xNi@Al2O3 catalysts with different Ni content was prepared by impregnation combustion method, the catalytic performance for CO methanation in a slurry‐bed reactor at low‐temperature was studied, and the structure of the catalysts was characterized by X‐ray diffraction, N2 adsorption–desorption, temperature‐programmed reduction of H2, transmission electron microscope, and H2 chemisorption. The results show that as Ni content increased from 5 to 45%, the crystallite size of metallic Ni increased and the specific surface area decreased, while as the Ni content was between 25 and 45%, the metal Ni surface area firstly increased and was then maintained at around 10 m2·g−1. The catalytic activity of xNi@Al2O3 catalysts increased as the Ni content rose from 5 to 25%, and then remained constant as the Ni content continued to rise. Under the reaction conditions of 300 °C, 1 MPa, and 3000 mL·g−1·h−1, 25Ni@Al2O3 catalyst exhibited the best catalytic performance; the CO conversion and the CH4 selectivity reached 94.3 and 93.7%, respectively. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.