Is an acidic environment the optimal direction for CO2 electroreduction? A study using porous membranes

초록

An acidic environment is considered economically favorable for the CO2 reduction reaction (CO2RR) due to its potential for high single-pass conversion (SPC). Here, we reassessed the economic feasibility of acidic CO2RR compared with neutral CO2RR in terms of energy efficiency and anode stability. To investigate the intrinsic characteristics of acidic CO2RR, a porous membrane (PM)-based electrode assembly was employed. Although acidic CO2RR enhances activity in alkaline regions and suppresses CO2 crossover in acidic regions, this dualenvironment configuration inherently increases cell voltage. In addition, acidic conditions accelerated anode catalyst dissolution. Despite the lower SPC in neutral media, techno-economic and life cycle analyses revealed that a neutral PM system provides superior economic feasibility compared with an acid-cation exchange membrane due to its lower cell voltage and improved anode stability. This work provides new insight into selecting optimal reaction environments for CO2 electrolysis technologies.

키워드