Electrochemical conversion of carbon dioxide (CO
2) using renewable electricity is an attractive approach for sustainable production of fuels and chemicals. Copper (Cu) has a unique capability of catalyzing carbon-carbon (C-C) bond formation to form high-value multi-carbon (C
2+) products. While highly alkaline electrolytes are often used to enhance C
2+ selectivity, the inevitable reaction of hydroxide ions with CO
2 to form undesired carbonates at the electrode-electrolyte interface disrupts the electrolysis process. This fundamental challenge can be solved by decoupling the CO
2 electrolysis into a two-step process, where CO
2 is first electrochemically reduced to carbon monoxide (CO) at neutral conditions, followed by CO electroreduction to produce C
2+ chemicals in alkaline environments. The feasibility of two-step tandem CO
2 electrolysis has been demonstrated experimentally by Romero Cuellar and co-workers [1], who reported a total CO
2 reduction current density of 300 mA/cm
2 with a cumulative Faradaic efficiency of 62% towards C
2+ products. However, the system is far from optimized when compared to standalone CO
2 and CO electrolysis technologies. In this talk, we will present the latest development of the tandem CO
2 electrolysis process for multicarbon chemical production, including the electrocatalyst design, reactor engineering, process optimization, and techno-economic analysis. Additionally, we will discuss the future opportunities for carbon dioxide utilization through tandem and hybrid processes [2].
Reference:
[1] Romero Cuellar, N.S., Scherer, C., Kaçkar, B., Eisenreich, W., Huber, C., Wiesner-Fleischer, K., Fleischer, M., and Hinrichsen, O. Two-step electrochemical reduction of CO2 towards multi-carbon products at high current densities. J. CO2 Util. 2020; 36: 263-275.
[2] Overa, S., Feric, T. G., Park, A. H. A.* & Jiao, F.* Tandem and Hybrid Processes for Carbon Dioxide Utilization. Joule 5, 8-13 (2021). doi: 10.1016/j.joule.2020.12.004