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

CO 2 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 CH 4 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 CeO 2 supporting ruthenium (3 wt%), synthesized by the one-pot hydrothermal method followed by a reduction in H 2 at 500 °C. Catalyst morphology, and Ru reducibility and dispersion were investigated by XRD, FE-SEMEDS microscopy, BET, H 2 -TPR and H 2 -TPD. The catalytic properties for the CO 2 methanation were tested at atmospheric pressure with a stoichiometric ratio of the reagents (CO 2 : H 2 = 1: 4). The one-pot synthesis of Ru(3 wt%)/CeO 2 produced an unexpected nanocube morphology with a high surface area, favoring a very high Ru dispersion (50%) corresponding to an average particle dimension < 2 nm. The catalyst shows good catalytic performances reaching 70% of CO 2 conversion at 350 °C, with 98% of selectivity towards CH 4 . 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 processes.