Synthetic Natural Gas Production from CO2 and Renewable H2: Towards Large-scale Production of Ni–Fe Alloy Catalysts for Commercialization

Synthetic natural gas (SNG) is one of the promising energy carriers for the excessive electricity generated from variable renewable energy sources. SNG production from renewable H₂ and CO₂  via catalytic CO₂ methanation has gained much attention since CO₂ emissions could be simultaneously reduced. In this study, Ni–Fe/(Mg,Al)O_x alloy catalysts for CO₂ methanation were prepared via hydrotalcite precursors using a rapid coprecipitation method. The effect of total metal concentration on the physicochemical properties and catalytic behavior was investigated. Upon calcination, the catalysts showed high specific surface area of above 230 m² g⁻¹. Small particle sizes of about 5 nm were obtained for all catalysts, even though the produced catalyst amount was increased by 10 times. The catalysts exhibited excellent space-time yield under very high gas space velocity (34,000 h⁻¹), irrespective of the metal concentration. The CO₂ conversions reached 73–79% at 300 °C and CH₄ selectivities were at 93–95%. Therefore, we demonstrated the potential of large-scale production of earth-abundant Ni–Fe based catalysts for CO₂ methanation and the Power-to-Gas technology.