Electrochemical reactors for CO2 conversion

Abstract

Increasing risks from global warming impose an urgent need to develop technologically and economically feasible means to reduce CO2 content in the atmosphere. Carbon capture and utilization technologies and carbon markets have been established for this purpose. Electrocatalytic CO2 reduction reaction (CO2RR) presents a promising solution, fulfilling carbon-neutral goals and sustainable materials production. This review aims to elaborate on various components in CO2RR reactors and relevant industrial processing. First, major performance metrics are discussed, with requirements obtained from a techno-economic analysis. Detailed discussions then emphasize on (i) technical benefits and challenges regarding different reactor types, (ii) critical features in flow cell systems that enhance CO2 diffusion compared to conventional H-cells, (iii) electrolyte and its effect on liquid phase electrolyzers, (iv) catalysts for feasible products (carbon monoxide, formic acid and multi-carbons) and (v) strategies on flow channel and anode design as next steps. Finally, specific perspectives on CO2 feeds for the reactor and downstream purification techniques are annotated as part of the CO2RR industrial processing. Overall, we focus on the component and system aspects for the design of a CO2RR reactor, while pointing out challenges and opportunities to realize the ultimate goal of viable carbon capture and utilization technology.