Optimizing the Electrochemical Reduction of CO₂ to Formate: A State-of-the-Art Analysis

Abstract

The electrochemical reduction of carbon dioxide to formate is an appealing carbon utilization method as it can be performed at room temperature and pressure, it only requires two electrons, and it has a high atom efficiency. This reaction has been known and studied for decades, but currently there is no commercial process practiced. This Perspective compares over 500 experimental data points from 65 scientific publications and patents and identifies the gas diffusion electrode as the best technology to scale this reaction. We further discuss the complex layers that make up a gas diffusion electrode and view what has been studied with respect to this reaction. Finally, we identify critical areas where more research can provide crucial understandings to allow this technology to become a commercial process.

Efficiency and selectivity of CO2 reduction to CO on gold gas diffusion electrodes in acidic media

“…Generating CO electrochemically can enable a less centralized CO production chain by allowing for on-site CO production on demand and eliminate transportation hazards and costs. Nevertheless, in order to achieve CO 2 electrolysis to CO at a commercial scale, three main key figures of merit are desired: high current efficiency and current density, low cell potential, and no dependency of these variables on the electrode size 4 .…”

“…It can be produced via the electrochemical reduction of CO 2 (CO 2 R), and, provided the electricity comes from zero emission technologies, the carbon cycle can be closed 2 . CO is among the most economically viable products that can be obtained through the electrocatalytic reduction of CO 2 as it has a high ratio of molecular weight per electron transferred [3][4][5] . Generating CO electrochemically can enable a less centralized CO production chain by allowing for on-site CO production on demand and eliminate transportation hazards and costs.…”

Towards Sustainable Oxalic Acid from CO2and Biomass

“…A comprehensive Review by Philips et al. discusses the importance of electrode design and suggests that industrially relevant yields and efficiencies will most likely require gas‐diffusion electrodes and intelligent cell designs [33] . Pilot or commercial scale tests are yet to prove the scalability and viability of this process.…”

“…Liquid Light, now part of Avantium, has successfully developed the gas‐diffusion electrode‐driven formate production from CO 2 [30–32] . These electrodes are technology leaders due to the stability, scale, and performance of this CO 2 conversion [33] . The formate produced in the electrochemical cells is further “upcycled” to oxalate using a process called formate coupling, where two formate molecules combine to oxalate with the release of hydrogen [34,35] .…”

Electroreduction of Carbon Dioxide into Formate: A Comprehensive Review

“…reviewed inorganic cathode materials. Recently, Philips et al [38] . compared several types of electrodes and cell configurations in terms of current efficiency toward the formation of formate.…”