Electrochemical Carbon Dioxide Capture and Concentration

Abstract

Electrochemical carbon capture and concentration (eCCC) offers a promising alternative to thermochemical processes as it circumvents the limitations of temperature-driven capture and release. This review will begin by discussing the history of eCCC, describing early work in the field and the motivation for pursuing such a process. We will then transition towards discussing more recent approaches, with a heavier emphasis on methods that employ redox mediators to facilitate CO2 capture and release. These methods rely more on optimization through chemical design and include pH-mediated systems, electrochemically-mediated amine regeneration, and direct capture with redox-active molecules. For each approach, we provide a general overview of the system, discuss redox mediator chemistries that have been studied in literature, and highlight requirements for future generations of redox mediators. We also describe previous demonstrations of each method and current cell/system designs that have been used at the lab-scale. To conclude, we summarize achievements in the field, current challenges, and opportunities for improving these technologies. Overall, this review is a comprehensive survey of the eCCC field and evaluates the chemical, theoretical, and electrochemical engineering aspects of this approach. We hope this work can be used to assist the community in the development of modern economical eCCC technologies that can be utilized in large-scale CCS processes.

Aqueous Electrochemical and pH Studies of Redox-Active Guanidino Functionalized Aromatics for CO2 Capture

“…The raw frame data was processed using SAINT 2 and SADABS 3 to yield the reflection data file. Subsequent calculations were carried out by using the SHELXTL 4 program package. There were no systematic absences nor any diffraction symmetry other than the Friedel condition.…”

“…The release of CO 2 is achieved by heating the sorbent (383 K for monoethanolamine). 3,4 However, these thermal-swing methods can only achieve 5−40% of the maximum theoretical energy efficiency. 1,5 Electrochemical methods can achieve greater theoretical energy efficiencies.…”

“…1,5 Electrochemical methods can achieve greater theoretical energy efficiencies. 4,6 One common motif for ambient electrochemical CO 2 capture and concentration uses redox active molecules that either (1) directly bind to and release CO 2 or (2) modify the pH of aqueous solutions (Scheme 1A). 7 In the first approach, redox carriers bind CO 2 in their electron-rich reduced form (Scheme 1A, red pathway).…”

Assessing the Kinetics of Quinone–CO2 Adduct Formation for Electrochemically Mediated Carbon Capture

“…K binding is calculated using eq 5, 27 which has been previously adopted to evaluate the CO 2 -binding strength. 17,28 = [ ] ( )…”

Redox-Mediated pH Swing Systems for Electrochemical Carbon Capture

“…14,15 In contrast, electrochemical carbon capture, featuring isothermal operation and nonvolatile redox-active materials, offers a promising alternative. 10,16 Early studies demonstrated the use of quinone derivatives in electrochemical systems in organic solvents. 17−19 Later, aqueous systems, including the development of electrochemical-mediated amine regeneration (EMAR) developed by our laboratory in 2013, played a significant role in advancing this field.…”