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

• Adding Fe to magnetic Ni catalyst improved CO 2 methanation efficiency and selectivity. • Magnetic Ni 8 Fe 2 converted >80% of CO 2 to methane at a low temperature of 150 °C. • Optimal catalyst reduction temperature determined as 200 °C. 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 CO 2 to CH 4 from H 2 obtained from renewable energy. In this study, Ni–Fe catalysts with different Ni/Fe ratios were prepared for high-efficiency CO 2 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. The catalyst with the best performance for CO 2 methanation had a ratio of Ni to Fe of 8/2 (Ni 8 Fe 2). The Ni 8 Fe 2 catalyst could convert over 80% of CO 2 to methane at 150 °C. In addition, the CH 4 selectivity of CO 2 methanation was 95% when the reaction conditions were controlled at H 2 /CO 2 = 4 and GHSV ∼1000 h⁻¹. The low cost and simple preparation of these Ni–Fe catalysts have high potential for future commercialization. [Display omitted] [ABSTRACT FROM AUTHOR]