RhNi/CeO₂ catalytic activation of alumina open cell foams by dip-spin coating for the CO₂ methanation of biogas

Production of CH₄ by methanation of biogas provides a promising route towards sustainable energy production for the future. Utilization of biogas from biomass as CO₂ source combines the advantage of reduction of greenhouse gas emissions producing a fuel with high energy density. In this study we apply a dip-spin coating method for washcoating Ni(7.5 wt%)Rh(0.5 wt%)/CeO₂ catalyst on alumina open cell foams with different cell densities (20, 30 and 40 PPI). The catalytic activity of the structured samples was assessed using a gas mixture that simulates a typical biogas composition (CH₄ = 60%vol; CO₂ = 40%vol). The effects of the reaction temperature (300–600 °C) and H₂/CO₂ molar ratio in the feed (3–5) on the CO₂ conversion and CH₄ selectivity were evaluated under a gas hourly space velocity (GHSV) of 5100 h⁻¹. All samples showed appreciable CO₂ conversion ranging between 62.5 and 66.7% at reaction temperature of 500–600 °C, and a CH₄ productivity of 3.4 mol_CH4·g_Me⁻¹·h⁻¹ was obtained with the catalyst supported on open cell foam with 30 and 20 PPI under a reaction temperature of 400 °C.