(Invited) Opportunities and Challenges for Biopolar Membrane-Based Electrosynthesis

Abstract

Over the last 3 decades, research on CO2 abatement technologies centered solely on carbon capture and storage (CCS). Here, technology focus is in the design of separations technologies to capture CO2 from concentrated point (e.g. flue gas) or dilute distributed sources (e.g. atmosphere) using amine absorption, adsorption, and membranes. Most of these technologies involve adsorbing or absorbing CO2 gas, releasing this gas, and then pressurizing it for storage. Thus, a number of different subsystems and specialized new equipment are needed resulting in high capital and operating costs. As a result, CO2 capture for CCS is economically unfavorable in the absence of utilization routes for the captured CO2. Electrolysis of CO2 is a viable potential pathway toward attaining utilization; however, carbon loss in traditional electrolysis architectures is a large limitation. To overcome this challenge, movement toward bipolar-membrane (BPM) based electrolysis cells have been proposed as a viable option. BPMs contain an anion and a cation exchange layer. At the interface of these membranes, a junction potential forms when a electric field is applied across the membrane. Thus, within a BPM electrolysis cell, charge balancing occurs through water electro dissociating at the interface of the anion and cation membrane, thereby forming charge carriers in the form of OH- and H+. The production of acid and base in situ allows for a continuous process with low carbon losses. The primary aim of this talk is to discuss the challenges and opportunities that exist with the development of proper catalyst and membranes for these systems for carbon capture and electrofuel production.