Boosting electrochemical CO2 reduction to CO by regulating pressure in zero-gap electrolyzer
The electrochemical reduction reaction of CO2 presents a promising strategy for both CO2 utilization and renewable energy storage. However, for this process to be economically viable, it must achieve high energy efficiency, high product selectivity, and suppression of the hydrogen evolution reaction...
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| Format: | Article |
| Language: | English |
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Elsevier
2025-10-01
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| Series: | Journal of CO2 Utilization |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2212982025001635 |
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| author | Muhammad Shakir Hussain Sheraz Ahmed Chirong Sun Hyung-Suk Oh Jaehoon Kim |
| author_facet | Muhammad Shakir Hussain Sheraz Ahmed Chirong Sun Hyung-Suk Oh Jaehoon Kim |
| author_sort | Muhammad Shakir Hussain |
| collection | DOAJ |
| description | The electrochemical reduction reaction of CO2 presents a promising strategy for both CO2 utilization and renewable energy storage. However, for this process to be economically viable, it must achieve high energy efficiency, high product selectivity, and suppression of the hydrogen evolution reaction (HER) at low cell voltages and industrially relevant current densities. Thus, this paper introduces a high-pressure zero-gap membrane electrode assembly electrolyzer that uses pristine silver nanoparticles (<150 nm) as the cathode catalyst for CO2-to-CO conversion. Operating at elevated CO2 pressures of up to 1.5 MPa and in a highly alkaline environment (2 M KOH) considerably enhanced CO selectivity and energy efficiency by reducing ohmic losses and improving reaction kinetics. At an optimized pressure of 1.5 MPa, a high current density of –350 mA cm⁻2 was sustained at an applied cell voltage of –3.2 V (–3.0 V, IR-compensated), achieving over 70 % CO Faradaic efficiency and 32 % CO energy efficiency. High-pressure operation also suppressed HER by increasing the local CO2 concentration at the catalyst surface, thereby improving CO selectivity. Additionally, salt precipitation mechanisms and their effect on catalyst deactivation were discussed. |
| format | Article |
| id | doaj-art-9c86021067554bc7bf5f1a0b8f4f0969 |
| institution | Kabale University |
| issn | 2212-9839 |
| language | English |
| publishDate | 2025-10-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of CO2 Utilization |
| spelling | doaj-art-9c86021067554bc7bf5f1a0b8f4f09692025-08-20T03:47:03ZengElsevierJournal of CO2 Utilization2212-98392025-10-0110010317910.1016/j.jcou.2025.103179Boosting electrochemical CO2 reduction to CO by regulating pressure in zero-gap electrolyzerMuhammad Shakir Hussain0Sheraz Ahmed1Chirong Sun2Hyung-Suk Oh3Jaehoon Kim4School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-Ro, Jangan-Gu, Suwon, Gyeonggi-Do 16419, Republic of KoreaSchool of Mechanical Engineering, Sungkyunkwan University, 2066, Seobu-Ro, Jangan-Gu, Suwon, Gyeonggi-Do 16419, Republic of KoreaSchool of Mechanical Engineering, Sungkyunkwan University, 2066, Seobu-Ro, Jangan-Gu, Suwon, Gyeonggi-Do 16419, Republic of KoreaClean Energy Research Center, Korea Institute of Science and Technology (KIST), Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea; School of Advanced Materials Science & Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea; KIST-SKKU Carbon-Neutral Research Center, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea; Corresponding author at: Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea.School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-Ro, Jangan-Gu, Suwon, Gyeonggi-Do 16419, Republic of Korea; School of Mechanical Engineering, Sungkyunkwan University, 2066, Seobu-Ro, Jangan-Gu, Suwon, Gyeonggi-Do 16419, Republic of Korea; Sungkyunkwan Advanced Institute of Nano Technology, Sungkyunkwan University, 2066, Seobu-Ro, Jangan-Gu, Suwon, Gyeonggi-Do 16419, Republic of Korea; Correspondence to: School of Mechanical Engineering, School of Chemical Engineering, and Sungkyunkwan Advanced Institute of Nano Technology, Sungkyunkwan University, 2066, Seobu-Ro, Jangan-Gu, Suwon, Gyeonggi-Do 16419, Republic of Korea.The electrochemical reduction reaction of CO2 presents a promising strategy for both CO2 utilization and renewable energy storage. However, for this process to be economically viable, it must achieve high energy efficiency, high product selectivity, and suppression of the hydrogen evolution reaction (HER) at low cell voltages and industrially relevant current densities. Thus, this paper introduces a high-pressure zero-gap membrane electrode assembly electrolyzer that uses pristine silver nanoparticles (<150 nm) as the cathode catalyst for CO2-to-CO conversion. Operating at elevated CO2 pressures of up to 1.5 MPa and in a highly alkaline environment (2 M KOH) considerably enhanced CO selectivity and energy efficiency by reducing ohmic losses and improving reaction kinetics. At an optimized pressure of 1.5 MPa, a high current density of –350 mA cm⁻2 was sustained at an applied cell voltage of –3.2 V (–3.0 V, IR-compensated), achieving over 70 % CO Faradaic efficiency and 32 % CO energy efficiency. High-pressure operation also suppressed HER by increasing the local CO2 concentration at the catalyst surface, thereby improving CO selectivity. Additionally, salt precipitation mechanisms and their effect on catalyst deactivation were discussed.http://www.sciencedirect.com/science/article/pii/S2212982025001635CO2 reductionZero-gap membrane electrode assemblyCO selectivityCurrent densityFaradaic efficiency |
| spellingShingle | Muhammad Shakir Hussain Sheraz Ahmed Chirong Sun Hyung-Suk Oh Jaehoon Kim Boosting electrochemical CO2 reduction to CO by regulating pressure in zero-gap electrolyzer Journal of CO2 Utilization CO2 reduction Zero-gap membrane electrode assembly CO selectivity Current density Faradaic efficiency |
| title | Boosting electrochemical CO2 reduction to CO by regulating pressure in zero-gap electrolyzer |
| title_full | Boosting electrochemical CO2 reduction to CO by regulating pressure in zero-gap electrolyzer |
| title_fullStr | Boosting electrochemical CO2 reduction to CO by regulating pressure in zero-gap electrolyzer |
| title_full_unstemmed | Boosting electrochemical CO2 reduction to CO by regulating pressure in zero-gap electrolyzer |
| title_short | Boosting electrochemical CO2 reduction to CO by regulating pressure in zero-gap electrolyzer |
| title_sort | boosting electrochemical co2 reduction to co by regulating pressure in zero gap electrolyzer |
| topic | CO2 reduction Zero-gap membrane electrode assembly CO selectivity Current density Faradaic efficiency |
| url | http://www.sciencedirect.com/science/article/pii/S2212982025001635 |
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