Electrochemical reduction of CO2 in the captured state using aqueous or nonaqueous amines

Integrated Capture and Solar-driven Utilization of CO2 from Flue Gas and Air

“…Subsequent CPE studies (for 10 h) revealed an optimum CO production at -1.85 V vs. Fc/Fc + with 19.0±1.4% FECO (Figures 2e, S11). Isotopic labelling experiments with captured 13 CO2 in both the aqueous (TEA/H2O) and non-aqueous (NaOH/EG) medium showed only 13 C labelled CO as reduction product during FTIR analysis of the headspace gas, confirming that CO was derived from captured CO2 (Figure 2f). ) with CoPcNH2@MWCNT cathode in a two-compartment three-electrode configuration.…”

“…The solution was further purged with N2 (15 min) to remove any physically dissolved CO2 (Figure S2). 13 C nuclear magnetic resonance ( 13 C-NMR) spectra of the post-capture solutions revealed that under these conditions, MEA and DEA captured 0.75±0.07 and 0.77±0.10 mol CO2 per mol amine, respectively, as bicarbonate and carbamate species. 27 In contrast, the tertiary amines TEA and DABCO captured CO2 only as bicarbonate salts (0.60±0.05 and 0.85±0.08 mol CO2 per mol amine, respectively, after 2 h; Scheme 1, eq 1-2; Figure S3).…”

“…40,41 The capture was done by purging simulated flue gas through capture solutions (1 M TEA/H2O or NaOH/EG) for 6 h at 30 mL min -1 flowrate. 13 C-NMR analysis showed that after 6 h, TEA/H2O captured 0.38±0.05 mol CO2 per mol TEA (as bicarbonate salt), and the NaOH/EG solution captured 0.90±0.04 mol CO2 per mol NaOH as sodium glycolate carbonate. Electrochemical CPE of the post-capture solutions with CoPcNH2@MWCNT cathode at optimized potentials (-0.7 V vs. RHE or -1.85 V vs. Fc/Fc + ) showed syngas production with FECO 24.0±0.9% and 11.9±0.3% in the TEA/H2O and NaOH/EG medium, respectively (Figure S20).…”

“…8,9 Direct solar-driven utilization of captured CO2 species is therefore a more attractive way to reach net-zero carbon cycle, but barely explored due to their thermodynamic stability. 10,11,12,13 Thermo-catalytic hydrogenation of captured CO2 has recently been reported at elevated temperatures (100-150 ºC). [14][15][16] Electrochemical reduction of alkanolamine captured CO2 can also be achieved over metallic electrodes (Ag, Cu, etc.)…”

Reactive Capture of CO2: Opportunities and Challenges

“…In this Perspective, we aim to provide an overview of reactive capture of CO 2 (RCC), which is defined as the direct conversion of captured CO 2 into a product without an intermediate step where CO 2 is intentionally released (Figure 1). Numerous reviews have appeared recently that have a narrower focus than this Perspective and therefore offer a more detailed analysis of certain subsets of RCC, including electrochemical RCC, 1,2 thermal homogeneous RCC, 3,4 thermal heterogeneous RCC, 5 and electrochemical reactor design for RCC. 6 In this Perspective, the section 1 provides some tutorial-style definitions, illuminates jargon and units, and provides some context and scope for RCC within the broad landscape of CO 2 chemistries and goals for greenhouse gas emissions.…”