On the viability of electrochemical carbon dioxide in-situ resource utilization to produce chemical feedstocks on Mars

Abstract

The long-term, crewed exploration of Mars is a priority for both national and private space entities. Given economical constraints on the mass sent off-world from Earth, in situ resource utilization (ISRU) through ultra-low temperature CO2-H2O electrolyzer technology that is fed using the Martian atmosphere’s CO2 (∼95 %) and the subsurface Martian water cycle (enabled by perchlorate salts that depress the Martian brine’s freezing point to < 213 K) has been proposed as a pathway towards fuel and chemical feedstock. Herein we applied a validated, computationally frugal electrolyzer model to a Martian CO2-H2O electrolyzer and examined its viability. Through a judicious combination of catalysts, such electrolyzers could produce O2, CO, HCHO, CH3OH, CH4, C2H4, and C2H5OH even at ambient Martian temperatures (∼237 K). Our modeling herein shows the theoretical production of these key resources in acidic electrolyzers to be at a scalable rate of 0.052 – 1.13 g per cm2 per day of CO, 0.0004 – 0.086 g per cm2 per day of CH3OH, 0.001–0.048 g per cm2 per day of CH4, 0.0164 – 0.171 g per cm2 per day of C2H4, 0.008 – 0.0125 g per cm2 per day of C2H5OH. A range of catalyst candidates were examined for product selectivity, energy efficiency and throughput. Ambient temperature CO2-H2O electrolysis is shown to be an energy efficient approach to chemical feedstocks needed for the sustained exploration of Mars and beyond. This model can inform future astronaut life support device development for NASA and other space faring entities.