About

At the Seo Research Group, we engineer molecular systems into functional devices and scalable processes. Our research focuses on developing electrochemical processes using stimulus-responsive materials to enable carbon capture and conversion. By integrating molecular engineering with energy and catalysis, we strive to create sustainable solutions for a cleaner future.

Research topics

• Organic chemistry
• Inorganic chemistry
• Chemistry
• Materials science
• Chemical engineering
• Environmental chemistry
• Physical chemistry
• Nanotechnology

Selected publications

• A Systematic Study of Pulsed Chronopotentiometry for Electrochemical CO2 Capture with Molecular Redox Mediators

  ChemRxiv · 2025-11-19

  articleSenior author

  Pulsed chronopotentiometry lowers cell voltage and energy input in aqueous Neutral Red–mediated electrochemical CO2 capture. A pulse–reverse current protocol achieves a specific electrical energy of 105.22 kJe mol−1 CO2, with an additional 26.72 kJe mol−1 CO2 used to stabilize the cell voltage (∼0.99 V for ±8/∓1 mA cm−2, 0.5/0.5 s), well below the direct-current baseline of 135.73 kJe mol−1 CO2 (∼1.43 V for ±3.5 cm−2) at matched current density (|javg|). These gains arise from a dual diffusion-layer model: pulsing maintains a thin, pulsation-controlled inner layer, while PRC refreshes the outer layer, suppressing parasitic reactions and polarization. Timing the on-period to Sand’s transition time keeps near-surface NR/NRH2 concentrations favorable without increasing solution flow rate. PRC offers a scalable route to improved efficiency owing to it aligns with various electrochemical cell architectures. Model-guided optimization could further minimize energy consumption while maintaining stability.

  PublisherDOI

• Electron-Leveraging Strategy for Enhanced Electrochemical CO₂ Capture Using Hemi-Labile Redox-Active Iron Complexes

  ECS Meeting Abstracts · 2025-07-11

  article1st authorCorresponding

  Electrochemical carbon capture (ECC) has emerged as a promising solution for CO 2 separation due to its potential for lower energy consumption, modularity, and compatibility with renewable energy sources. Recent research in electrochemical carbon capture systems has focused on reducing separation energy consumption by optimizing the electrochemical cell potential and maximizing the electron utilization. While electron utilization typically has a theoretical limit of 1, efforts to reduce energy consumption even further require surpassing this limit. To overcome this fundamental limitation, we introduce a novel electron-leveraging strategy that enhances electron utilization beyond unity, offering a pathway to improved energy efficiency in CO 2 capture processes. This work demonstrates an electrochemical cyclic CO 2 capture system based on Fe-EDDHA (ethylenediamine-N,N'-bis(2-hydroxyphenylacetic acid)), a redox-active coordination complex featuring hemi-labile ligands. The Fe-EDDHA complex undergoes electrochemical reduction at the metal center, inducing partial ligand dissociation that enables CO 2 capture through a pH-swing mechanism. To stabilize the reduced species and prevent undesired CO 2 reduction reactions, nicotinamide (NA) is introduced as a metal-center guardian, effectively enhancing system reversibility. The system was evaluated in aqueous solutions using 15% CO 2 as a simulated flue gas. Key experimental results show an electron utilization value of 1.43 , exceeding the theoretical limit of 1, which is attributed to the electron-leveraging mechanism enabled by the oxidation-state-dependent coordination behavior of Fe-EDDHA. A minimum operational energy of 22.6 kJ e /mol CO 2 was achieved under optimized conditions, with an average energy consumption of 63.7 ± 1.0 kJ e /mol CO 2 over 29 stable cycles. These values place the system’s performance within the competitive range of electrochemical and thermally driven carbon capture technologies. To elucidate the underlying mechanism, we conducted a series of electrochemical and spectroscopic analyses, including cyclic voltammetry (CV), UV-Vis spectroscopy, and ¹H/¹³C NMR studies. These analyses confirmed the role of NA in stabilizing the reduced Fe-EDDHA species, thereby suppressing inner-sphere electron transfer to CO 2 while maintaining the redox cycling stability. NMR temperature-dependent studies further revealed a dynamic exchange between free and bound NA, providing additional insights into the interaction between NA and the Fe(II) center. Our results highlight the critical role of hemi-labile ligands in expanding the molecular design space for redox-active materials. Unlike conjugated organic compounds, which expose their electron density to potential undesired reactions, the use of metal-centered redox-active complexes with coordinated ligands enables greater control over reactivity, stability, and performance. The electron-leveraging strategy demonstrated in this study establishes a foundation for achieving higher electron utilization and reduced energy consumption in ECC systems.

  PublisherDOI

• Leveraging Electrons for Electrochemical CO ₂ Capture Using a Hemi‐Labile Iron Complex

  Angewandte Chemie International Edition · 2025-08-04 · 2 citations

  articleOpen access1st authorCorresponding

  Abstract Climate change, driven by anthropogenic carbon emissions, demands urgent action to prevent a 2050 tipping point. With CO 2 levels at 427 ppm (50% above pre‐industrial levels), deploying energy‐efficient carbon capture technologies is crucial. Electrochemical carbon capture processes that have been touted to have the potential to meet these needs rely on the applied cell voltage, and electron utilization (CO 2 molecules separated per electron), which has generally been asserted to have a theoretical limit of one. Here, we introduce an electron‐leveraging strategy to enhance electron utilization beyond this limit to 1.43 by employing Fe‐EDDHA, a redox‐active coordination complex having a ligand with multiple hemi‐labile coordination sites. The reversibility and robustness of the system were enabled by the efficient prevention of CO 2 reduction upon the introduction of nicotinamide as a guardian of the iron(2+) center. The proof‐of‐concept cyclic system exhibits a minimum operational energy of 22.6 kJ e mol −1 and an average of 63.7 kJ e mol −1 over 29 cycles, using a simulated flue gas (15% CO 2 ). Our electron‐leveraging strategy holds promise for advancing energy‐efficient electrochemical carbon capture technologies, and offers an alternative to prevalent redox potential shifting methods proposed to mitigate undesired electron transfer reactions in redox‐active materials across diverse operational conditions.

  PublisherOA PDFDOI

• Enhancing Efficiency of Electrochemical Carbon Capture Using Pulsed Chronopotentiometry with Hydrophilic Graphite Electrode

  ECS Meeting Abstracts · 2025-07-11

  articleSenior author

  Achieving carbon neutrality is an urgent global goal, aiming to balance industrial development with preserving the Earth’s livability. The Intergovernmental Panel on Climate Change (IPCC) identifies carbon dioxide (CO₂) as a primary anthropogenic greenhouse gas contributing to climate change. The continuous emission of CO₂ into the atmosphere has resulted in a higher concentration (422 ppm) compared to preindustrial levels (280 ppm), leading to erratic weather patterns and extreme temperatures. Carbon capture technologies offer a practical solution to this challenge, enabling continued industrial and cultural progress while mitigating negative environmental effects. While conventional thermal methods require 230-800 kJ of thermal energy per mole of CO₂ separation, electrochemical methods provide an energy-efficient approach for the carbon capture process, operating under isothermal conditions. Recently, Seo et al. reported an electrochemical direct air capture method using redox-active Neutral Red (NR), an organic dye compound, which demonstrates high electron utilization and theoretically low energy consumption, suggesting a sustainable alternative to conventional thermal technologies. However, initial tests revealed operational voltages exceeding 2 V, attributed to limited electron transfer kinetics and transport. Two primary obstacles were identified: (1) insufficient chemical properties and active surface area in graphite felt electrodes, and (2) restricted NR transport due to low concentration.[1][2][3] Herein, we present an optimized electrochemical carbon capture operation using modified graphite felt electrodes to enhance wettability and pulsed chronopotentiometry to reduce concentration overpotentials. The carbon capture system integrates electrode material modification and pulsed chronopotentiometry to enhance electron transfer efficiency, reduce energy consumption, and address challenges such as poor wettability and NR polymerization. To improve the electrode-electrolyte interaction, graphite felt electrodes were modified by introducing oxygen-containing functional groups on their surface. This modification significantly enhanced the wettability of the electrodes, as demonstrated by water contact angle measurements, and facilitated efficient electron transfer between the electrode and electrolyte, which is critical for minimizing energy consumption. The choice of electrode materials and operational parameters was thus optimized to enable low-resistance electrochemical reactions. Cyclic voltammetry experiments revealed that the modified graphite felt exhibited a higher current response at the same voltage compared to the pristine electrode. This improvement translated into a substantial reduction in operating cell voltages, with a reduction of 19.5%, decreasing from an average of 1.18 V to 0.95 V. A notable challenge during the reduction process was the polymerization of Neutral Red (NR), which resulted in the loss of active material in the electrolyte, thereby increasing the cell voltages. To address this issue, pulsed chronopotentiometry was employed. This technique periodically applies a low opposing current, minimizing polymerization and reducing overpotential. By alternating between run and rest currents, the method effectively improved system efficiency. With pulsed chronopotentiometry, the redox reactions of NR were achieved at significantly lower operating voltages, demonstrating a 43% reduction (1.18 V) compared to constant chronopotentiometry (2.07 V) at a current density of 8 mA/cm 2 and using 15% CO 2 . The electrochemical carbon capture system in this study employed a two-electrode configuration, featuring a customized nylon frame packed with graphite felt electrodes, with the two compartments separated by an anion exchanging membrane. The electrochemical cell was connected to two containment vessels, where consistent 15% CO2 input stream was introduced and the output measured by an FTIR CO 2 sensor. A peristaltic pump was used to circulate the solution throughout the system. Two containment conditions with varying activation percentages were implemented, with a working capacity of 25% applied. The electrochemical approach using pulsed chronopotentiometry with modified graphite felt electrodes achieved operating cell potentials as low as 0.95 V, with an estimated energy consumption of 160 kJe/mol CO₂. This underscores its potential as an efficient, sustainable carbon capture strategy, highlighting the importance of electrode material modification and optimized operational strategies in enhancing energy efficiency and performance. Keywords: Electrochemistry, Carbon Capture, pH Swing, Pulsed Chronopotentiometry, Neutral Red, Graphite felt [1] IPCC, 2021: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (2021). [2] H. Seo and T. A. Hatton, Nature Communications , 14 (2023). [3] H. Seo, M. P. Nitzsche, and T. Alan Hatton, Accounts of Chemical Research , 56 , 3153–3164 (2023). Figure 1

  PublisherDOI

• Leveraging Electrons for Electrochemical CO ₂ Capture Using a Hemi‐Labile Iron Complex

  Angewandte Chemie · 2025-08-04 · 1 citations

  articleOpen access1st authorCorresponding

  Abstract Climate change, driven by anthropogenic carbon emissions, demands urgent action to prevent a 2050 tipping point. With CO 2 levels at 427 ppm (50% above pre‐industrial levels), deploying energy‐efficient carbon capture technologies is crucial. Electrochemical carbon capture processes that have been touted to have the potential to meet these needs rely on the applied cell voltage, and electron utilization (CO 2 molecules separated per electron), which has generally been asserted to have a theoretical limit of one. Here, we introduce an electron‐leveraging strategy to enhance electron utilization beyond this limit to 1.43 by employing Fe‐EDDHA, a redox‐active coordination complex having a ligand with multiple hemi‐labile coordination sites. The reversibility and robustness of the system were enabled by the efficient prevention of CO 2 reduction upon the introduction of nicotinamide as a guardian of the iron(2+) center. The proof‐of‐concept cyclic system exhibits a minimum operational energy of 22.6 kJ e mol −1 and an average of 63.7 kJ e mol −1 over 29 cycles, using a simulated flue gas (15% CO 2 ). Our electron‐leveraging strategy holds promise for advancing energy‐efficient electrochemical carbon capture technologies, and offers an alternative to prevalent redox potential shifting methods proposed to mitigate undesired electron transfer reactions in redox‐active materials across diverse operational conditions.

  PublisherDOI

• Oxygen‐Stable Electrochemical CO₂ Capture using Redox‐Active Heterocyclic Benzodithiophene Quinone

  Angewandte Chemie · 2024-09-09 · 1 citations

  article

  Abstract Electrochemical carbon capture offers a promising alternative to thermal amine technology, which serves as the traditional benchmark method for CO 2 capture. Despite its technological maturity, the widespread deployment of thermal amine technologies is hindered by high energy consumption and sorbent degradation. In contrast, electrochemical methods, with their inherently isothermal operation, address these challenges, offering enhanced energy efficiency and robustness. Among emerging strategies, electrochemical carbon capture systems using redox‐active materials such as quinones stand out for their potential to capture CO 2 . However, their practical application is currently limited by their low stability in the presence of oxygen. We demonstrate that benzodithiophene quinone (BDT‐Q), a heterocyclic quinone, exhibits high stability in electrochemical carbon capture processes with oxygen‐containing feed gas. Conducted in a cyclic flow system with a simulated flue gas mixture containing 13 % CO 2 and 3.5 % O 2 for over 100 hours, the process demonstrates high oxygen stability with an electron utilization of 0.83 without significant degradation, indicating a promising approach for real world applications. Our study explores the potential of new heterocyclic quinone compounds in the context of carbon capture technologies.

  PublisherDOI

• Oxygen‐Stable Electrochemical CO₂ Capture using Redox‐Active Heterocyclic Benzodithiophene Quinone

  Angewandte Chemie International Edition · 2024-09-09 · 35 citations

  articleOpen access

  Abstract Electrochemical carbon capture offers a promising alternative to thermal amine technology, which serves as the traditional benchmark method for CO 2 capture. Despite its technological maturity, the widespread deployment of thermal amine technologies is hindered by high energy consumption and sorbent degradation. In contrast, electrochemical methods, with their inherently isothermal operation, address these challenges, offering enhanced energy efficiency and robustness. Among emerging strategies, electrochemical carbon capture systems using redox‐active materials such as quinones stand out for their potential to capture CO 2 . However, their practical application is currently limited by their low stability in the presence of oxygen. We demonstrate that benzodithiophene quinone (BDT‐Q), a heterocyclic quinone, exhibits high stability in electrochemical carbon capture processes with oxygen‐containing feed gas. Conducted in a cyclic flow system with a simulated flue gas mixture containing 13 % CO 2 and 3.5 % O 2 for over 100 hours, the process demonstrates high oxygen stability with an electron utilization of 0.83 without significant degradation, indicating a promising approach for real world applications. Our study explores the potential of new heterocyclic quinone compounds in the context of carbon capture technologies.

  PublisherOA PDFDOI

• Visible Light-Driven CO₂ Capture and Release Using Photoactive Pyranine in Water in Continuous Flow

  Journal of the American Chemical Society · 2024-08-12 · 22 citations

  article1st author

  The urgent need to address climate change and its environmental consequences demands innovative carbon capture technologies, given the relationship between rising global temperatures and increased atmospheric CO2 levels. Here, we present a reversible photochemical carbon capture and release strategy and system utilizing photoactive pyranine in an aqueous bicarbonate buffer system. Control experiments suggested that the photoacid effect occurs at the surface which contributes to CO2 release, complemented by the photothermal effect at the surface and in the bulk. A continuous flow setup employing a tube-in-tube configuration with a hollow fiber membrane demonstrates the efficiency and reliability of the visible light-driven carbon capture system, with the release of CO2 captured from a 15% CO2 feed in the dark, at a rate of 0.48 mmol CO2 per hour to a nitrogen sweep stream under light irradiation at 200 W/m2, a level comparable to solar intensity of visible light (150 W/m2 of blue light −250 W/m2 of blue and green light). The robustness and scalability of the system has been demonstrated, with long-term operation over 7 days yielding 60 mmol (1.34 L CO2 at STP) of cumulated CO2 separation. Additionally, we explored the potential for direct air capture, yielding 3 μmol of CO2 separation over 2 h of operation from a bicarbonate buffer solution saturated with ambient air (420 ppm). This work introduces the prospect of photoswing of carbon capture systems, which can avoid external energy input beyond solar irradiation, offering promising avenues for addressing the challenges associated with climate change.

  PublisherDOI

• Redox-Mediated pH Swing Systems for Electrochemical Carbon Capture

  Accounts of Chemical Research · 2023-11-10 · 47 citations

  article1st author

  ConspectusThe rising levels of atmospheric CO2 and their resulting impacts on the climate have necessitated the urgent development of effective carbon capture technologies. Electrochemical carbon capture systems have emerged as a potential alternative to conventional thermal systems based on amine solutions due to their modularity, energy efficiency, and lower environmental impact. Among these, aqueous electrochemical pH swing systems that capitalize on the pH dependence of dissolved inorganic carbon (CO2/HCO3–/CO32–) speciation to capture and release CO2 are of particular interest as they can be flexible in system design and in the range of electrochemical potentials used as well as being environmentally benign. In this Account, we present our recent findings in pH swing-based electrochemical carbon capture using redox-active materials, paving the way toward a sustainable solution for mitigating CO2 emissions.In the first section, we discuss the utilization of molecular redox-active organic materials in electrochemical carbon capture by the pH swing method. This electrochemical system configuration involves homogeneous aqueous electrolytes containing molecular redox-active compounds combined with inert carbon-based electrodes. We first present the development of redox-active amine and oxygen-insensitive neutral red (NR)-based systems. Notably, the discovery of 1-aminopyridinium (1-AP) as an electrochemically reversible compound enables efficient pH swing, leading to an impressive electron utilization of 1.25 mol of CO2 per mole of electrons. Additionally, we explore an oxygen-insensitive neutral red/leuconeutral red (NR/NRH2) redox system, which demonstrates potential applicability to direct air capture (DAC) systems with ambient air as a feed gas.The second section focuses on the utilization of inorganic nanomaterials for redox-active electrodes for pH swing-based electrochemical carbon capture. In this system configuration, we employ redox-active electrodes for inducing reversible pH swings in aqueous electrolytes without interrupting other ionic species, except protons. Specifically, we explore the effectiveness of manganese oxide (MnO2) electrodes for achieving selective CO2 removal from simulated flue gas. We then demonstrate a bismuth/silver (Bi/BiOCl, Ag/AgCl) nanoparticle electrode system as a sodium-insensitive pH swing system for extracting dissolved inorganic carbon (DIC) from simulated seawater with high electrochemical energy efficiency.Overall, these advances in pH swing-based electrochemical carbon capture offer promising preliminary solutions for combating climate change by capturing CO2 from dilute sources such as flue gas and ambient air as well as enabling direct carbon removal from ocean water. While these systems have demonstrated impressive energy efficiency and environmental benefits using redox-active materials, they represent only the beginning of our research journey. Further development and optimization are currently underway as we strive to unlock their full potential for large-scale implementation, paving the way toward a sustainable and carbon-neutral future.

  PublisherDOI

• Electrochemical direct air capture of CO2 using neutral red as reversible redox-active material

  Nature Communications · 2023 · 147 citations

  1st authorCorresponding
  • Chemistry
  • Materials science
  • Inorganic chemistry

  .

  PublisherOA PDFDOI

Frequent coauthors

• Timothy F. Jamison

  Massachusetts Institute of Technology

  11 shared

• T. Alan Hatton

  Massachusetts Institute of Technology

  10 shared

• Ji Ha Lee

  Shinshu University

  10 shared

• Heekyoung Choi

  Gyeongsang National University

  9 shared

• Jin‐Ho Ahn

  7 shared

• Yeonweon Choi

  Daejeon University

  7 shared

• Jong Hwa Jung

  7 shared

• Jaehyeon Park

  6 shared

Education

• M.S., Pharmacy

  Seoul National University

  2013

• B.S., Pharmacy

  Seoul National University

  2011