Improving the efficiency of Sabatier reaction through H₂O removal with low-pressure plasma catalysis

Abstract This study aimed to realize in situ resource utilization in deep-space missions. The Sabatier reaction is used to generate CH 4 from CO 2 , which accounts for 95% of the Martian atmosphere, and H 2 from H 2 O on Mars. In general, thermal catalysis at temperatures above 250 °C drives the process. This high-temperature process, however, causes catalyst deactivation due to overheating. Plasma catalysis drives low-temperature reactions by excitation and decomposition of source gases via electron impact. We investigated the effect of removing H 2 O from gas phase in the reaction with Cu and Ni catalysts using molecular sieves in this study. The reverse reaction can be aided by OH radicals derived from H 2 O. Therefore, CO 2 conversion increased from 49.4% to 69.1% for Cu catalysts with molecular sieves, and CH 4 selectivity increased from 3.49% to 6.33%. These findings imply that removing H 2 O can suppress the reverse reactions.