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 CH4 from CO2, which accounts for 95% of the Martian atmosphere, and H2 from H2O 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 H2O 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 H2O. Therefore, CO2 conversion increased from 49.4 to 69.1% for Cu catalysts with molecular sieves, and CH4 selectivity increased from 3.49 to 6.33%. These findings imply that removing H2O can suppress the reverse reactions.