Heteroatom Engineering Enables Oxygen-Tolerant Electrochemical Direct Air Capture
Abstract
Electrochemical direct CO2 capture using redox-active carriers offers an alternative to thermal amine scrubbing but requires molecules that combine strong CO2 binding with tolerance toward oxygen and water. Here, we show that incorporating pyridinic nitrogen into an ortho-quinone framework provides this combination in 1,10phenanthroline-5,6-dione (PD). Comparison of PD with phenanthrenequinone (PQ) and the analogue 1,10phenanthroline (PT) isolates the role of pyridinic nitrogen in tuning the redox potential and CO2 capture behaviour of the quinone core. Electrochemical measurements, density functional theory (DFT), in situ FT-IR, and 13C NMR spectroscopy support strong and reversible CO2 binding through the electrochemically reduced dianion (log𝐾 = 9.8). The capture chemistry established in homogeneous electrolyte was subsequently translated to PD immobilised on a carbon-felt electrode and demonstrated in a near-neutral aqueous electrolyte. Under a 9.3% CO2 feed, the PD-modified electrode sustained reversible CO2 capture and release over 16 h with an electron-utilisation efficiency of 96% and a minimum energy requirement of 44-56 kJ mol-1 CO2. Isotope-sensitive in situ FT-IR measurements and the pH response during aqueous cycling further support cation participation in charge compensation. These results establish heteroatom engineering as a molecular design strategy for developing oxygen- and water-tolerant quinone redox carriers and provide a pathway toward electrochemical CO2 capture from dilute emission streams.
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BibTeX
@misc{hazra2026heteroatom,
title = {{Heteroatom Engineering Enables Oxygen-Tolerant Electrochemical Direct Air Capture}},
author = {Abhijit Hazra and Esraa Ragab Kotob and Maryam Abdinejad},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010519/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010519/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Heteroatom Engineering Enables Oxygen-Tolerant Electrochemical Direct Air Capture
AU - Abhijit Hazra
AU - Esraa Ragab Kotob
AU - Maryam Abdinejad
PY - 2026
DA - 2026/10/15
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010519/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010519/v1
AB - Electrochemical direct CO2 capture using redox-active carriers offers an alternative to thermal amine scrubbing but requires molecules that combine strong CO2 binding with tolerance toward oxygen and water. Here, we show that incorporating pyridinic nitrogen into an ortho-quinone framework provides this combination in 1,10phenanthroline-5,6-dione (PD). Comparison of PD with phenanthrenequinone (PQ) and the analogue 1,10phenanthroline (PT) isolates the role of pyridinic nitrogen in tuning the redox potential and CO2 capture behaviour of the quinone core. Electrochemical measurements, density functional theory (DFT), in situ FT-IR, and 13C NMR spectroscopy support strong and reversible CO2 binding through the electrochemically reduced dianion (log𝐾 = 9.8). The capture chemistry established in homogeneous electrolyte was subsequently translated to PD immobilised on a carbon-felt electrode and demonstrated in a near-neutral aqueous electrolyte. Under a 9.3% CO2 feed, the PD-modified electrode sustained reversible CO2 capture and release over 16 h with an electron-utilisation efficiency of 96% and a minimum energy requirement of 44-56 kJ mol-1 CO2. Isotope-sensitive in situ FT-IR measurements and the pH response during aqueous cycling further support cation participation in charge compensation. These results establish heteroatom engineering as a molecular design strategy for developing oxygen- and water-tolerant quinone redox carriers and provide a pathway toward electrochemical CO2 capture from dilute emission streams.
ER -