Electrochemical Carbon Dioxide Capture and Release with a Redox-Active Amine

Abstract

Anthropogenic carbon dioxide (CO2) emission from the combustion of fossil fuels is a major contributor to global climate change and ocean acidification. The implementation of carbon capture and storage technologies has been proposed to mitigate the buildup of this greenhouse gas in the atmosphere. Among these technologies, direct air capture is regarded as a plausible CO2 removal tool whereby net negative emissions can be achieved. However, the separation of CO2 from air is particularly challenging due to the ultradilute concentration of CO2 in the presence of high concentrations of dioxygen and water. Here, we report a robust electrochemical redox-active amine system demonstrating a high electron utilization (i.e., mole of CO2 per mole of electrons) of up to 1.25 with the capture of two CO2 molecules per amine in an aqueous solution with a work of 101 kJe per moles of CO2. The capture of CO2 directly from ambient air as the feed gas presented an electron utilization of 0.78.

Challenges and opportunities in continuous flow processes for electrochemically mediated carbon capture

“…The NaHCO 3 can represent spent NaOH sorbent from point-source capture and DAC or the DIC in seawater. (G) pH swing EMCC with organic PCET molecules ( Huynh et al., 2016 ; Jin et al., 2022 ; Seo et al., 2022 ). (H) pH swing EMCC with proton (de)intercalation inorganic electrodes ( Rahimi et al., 2020a , 2020b ).…”

“… (G) pH swing EMCC with organic PCET molecules ( Huynh et al., 2016 ; Jin et al., 2022 ; Seo et al., 2022 ). (H) pH swing EMCC with proton (de)intercalation inorganic electrodes ( Rahimi et al., 2020a , 2020b ).…”

“…In addition to electrodialysis, the pH of aqueous solutions can also be modulated using dissolved redox-active organic molecules that undergo proton-coupled electron transfer (PCET, Figure 2 G) ( Huynh et al., 2016 ; Jin et al., 2022 ; Seo et al., 2022 ). In this scheme, electrochemical reduction of PCET molecules (symbolized as Q, Q + H 2 O + e − →QH + OH − ) raises the electrolyte pH for CO 2 capture, and the subsequent electrochemical oxidation of the reduced molecules (QH→Q + H + +e − ) acidifies the electrolyte for CO 2 release.…”

Confinement effects facilitate low-concentration carbon dioxide capture with zeolites

“…Thus, chemisorbents have been extensively investigated for trace CO 2 capture ( 7 ). Liquid amine and alkaline adsorbents as well as other types of chemisorbents (e.g., ionic liquids ( 8 ) and electric based membranes ( 9 )) have been investigated for the capture of CO 2 from low-concentration environments. However, the intensive energy requirements for desorption (60–120 kJ/mol) and slow kinetics may be problematic for processing the large quantities needed for the implementation of DAC with chemisorbents.…”

Activated Carbon Electrodes with Improved Sorption Capacity for Supercapacitive Swing Adsorption of Carbon Dioxide

“…7,8 To date, the most widely used technology for CO2 capture is amine scrubbing, which requires the use of corrosive, volatile, and toxic solvents. 9,10 Alternative technologies for carbon capture include pressure swing adsorption (PSA) and temperature swing adsorption (TSA) on porous sorbents such as zeolites and porous carbons. They are limited by energy intensive pressure and temperature gradients, relatively low CO2/N2 selectivity, and sensitivity to moisture in the gas mixture.…”