Effect of Ni/Fe ratio in Ni-Fe catalysts prepared under external magnetic field on CO2 methanation

Background: The power-to-gas (PtG) method has significant potential as a strategy for storing excess renewable energy in the form of synthetic natural gas. PtG involves the hydrogenation of CO2 to CH4 from H-2 obtained from renewable energy. Methods: In this study, Ni-Fe catalysts with different Ni/Fe ratios were prepared for high-efficiency CO2 methanation using chemical reduction with an external magnetic field. The Ni-Fe catalysts were characterized by XRD, inductively coupled plasma, and SEM-EDS measurements, and their performance and chemical properties were measured by H-2 temperature programmed reduction experiments. Significant findings: The catalyst with the best performance for CO2 methanation had a ratio of Ni to Fe of 8/2 (Ni8Fe2). The Ni8Fe2 catalyst could convert over 80% of CO2 to methane at 150 degrees C. In addition, the CH4 selectivity of CO2 methanation was 95% when the reaction conditions were controlled at H-2/CO2 = 4 and GHSV similar to 1000 h(-1). The low cost and simple preparation of these Ni-Fe catalysts have high potential for future commercialization. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.