CO2 Recycling into CH4 and H2O over Ru/CeO2 Catalyst Prepared by one-pot Synthesis

CO2 collected from the outdoor atmosphere or produced in an aerospace cabin, may be recycled to produce methane and water by the Sabatier reaction. This reaction is carried out over a catalyst to decrease the reaction temperature and increase the selectivity towards CH4 avoiding CO production. The practice of “in-situ resource utilization” needs a catalyst highly active at low temperatures, highly selective, and stable towards deactivation throughout the duration of the mission. This paper reports the catalytic activity of CeO2 supporting ruthenium (3 wt%), synthesized by the one-pot hydrothermal method followed by a reduction in H2 at 500 °C. Catalyst morphology and Ru reducibility and dispersion were investigated by XRD, FE-SEM-EDS microscopy, BET, H2-TPR and H2-TPD. The catalytic properties for the CO2 methanation were tested at atmospheric pressure with a stoichiometric ratio of the reagents (CO2: H2 = 1: 4). The one-pot synthesis of Ru(3wt%)/CeO2 produced an unexpected nanocube morphology with a high surface area, favouring a very high Ru dispersion (50%) corresponding to an average particle dimension < 2 nm. The catalyst shows good catalytic performances reaching 70% of CO2 conversion at 350 °C, with 98% of selectivity towards CH4. Carrying out the reaction for 12 hours at 500 °C, the catalyst shows no activity nor selectivity loss, appearing as a reliable catalyst for in-situ resource utilization and atmosphere revitalization processe