Deriving an Efficient and Stable Microenvironment for a CO<sub>2</sub> MEA Electrolyzer by Reverse Osmosis
Jae‐Yong Park, Eung‐Dab Kim, Sang-Kuk Kim, Chulwan Lim, Hyunchul Kim, Young‐Jin Ko, Jae‐Young Choi, Hyung‐Suk Oh, Woong Hee Lee
Abstract
In a membrane electrode assembly (MEA) electrolyzer based on a cation-exchange membrane, achieving an efficient and stable CO 2 reduction reaction (CO 2 RR) is challenging because the transport of protons, cations, and electro-osmotic water from the anode changes the balance of ions. Herein, we derived a microenvironment for stable and efficient CO 2 RR performance by using two strategies. First, a mixture of carbon and anion-exchange ionomer buffer layers is used to hold cations while managing water in local alkaline media. The second strategy involves pressurizing only the cathode side, resulting in a high local CO 2 concentration and enhancing the reverse osmosis phenomenon. The synergistic effects of these two strategies create an efficient microenvironment by managing water and cations, leading to a stable and efficient CO 2 RR operation. Our approach of reverse osmosis to balance cations and water is viable for industrial applications because pressurized CO 2 and MEA systems are efficient processes that can be commercialized.