Modulating the coordination environment of cobalt porphyrins for enhanced electrochemical nitrite reduction to ammonia
Abstract Electrocatalytic reduction of nitrate pollutants to produce ammonia offers an effective approach to realizing the artificial nitrogen cycle and replacing the energy‐intensive Haber‐Bosch process. Nitrite is an important intermediate product in the reduction of nitrate to ammonia. Therefore,...
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| Format: | Article |
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Wiley
2025-01-01
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| Series: | Carbon Energy |
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| Online Access: | https://doi.org/10.1002/cey2.657 |
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| author | Jingwei Han Hai Sun Fengkun Tian Wenwen Zhang Zonghang Zhang Ping She Jun‐Sheng Qin Heng Rao |
| author_facet | Jingwei Han Hai Sun Fengkun Tian Wenwen Zhang Zonghang Zhang Ping She Jun‐Sheng Qin Heng Rao |
| author_sort | Jingwei Han |
| collection | DOAJ |
| description | Abstract Electrocatalytic reduction of nitrate pollutants to produce ammonia offers an effective approach to realizing the artificial nitrogen cycle and replacing the energy‐intensive Haber‐Bosch process. Nitrite is an important intermediate product in the reduction of nitrate to ammonia. Therefore, the mechanism of converting nitrite into ammonia warrants further investigation. Molecular cobalt catalysts are regarded as promising for nitrite reduction reactions (NO2−RR). However, designing and controlling the coordination environment of molecular catalysts is crucial for studying the mechanism of NO2−RR and catalyst design. Herein, we develop a molecular platform of cobalt porphyrin with three coordination microenvironments (Co‐N3X1, X = N, O, S). Electrochemical experiments demonstrate that cobalt porphyrin with O coordination (CoOTPP) exhibits the lowest onset potential and the highest activity for NO2−RR in ammonia production. Under neutral, non‐buffered conditions over a wide potential range (−1.0 to −1.5 V versus AgCl/Ag), the Faradaic efficiency of nearly 90% for ammonia was achieved and reached 94.5% at −1.4 V versus AgCl/Ag, with an ammonia yield of 6,498 μg h−1 and a turnover number of 22,869 at −1.5 V versus AgCl/Ag. In situ characterization and density functional theory calculations reveal that modulating the coordination environment alters the electron transfer mode of the cobalt active center and the charge redistribution caused by the break of the ligand field. Therefore, this results in enhanced electrochemical activity for NO2−RR in ammonia production. This study provides valuable guidance for designing adjustments to the coordination environment of molecular catalysts to enhance catalytic activity. |
| format | Article |
| id | doaj-art-5a9c31ac1dab4fe6bfd7ba7efa4cb6a0 |
| institution | Kabale University |
| issn | 2637-9368 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Carbon Energy |
| spelling | doaj-art-5a9c31ac1dab4fe6bfd7ba7efa4cb6a02025-01-24T13:35:41ZengWileyCarbon Energy2637-93682025-01-0171n/an/a10.1002/cey2.657Modulating the coordination environment of cobalt porphyrins for enhanced electrochemical nitrite reduction to ammoniaJingwei Han0Hai Sun1Fengkun Tian2Wenwen Zhang3Zonghang Zhang4Ping She5Jun‐Sheng Qin6Heng Rao7State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, International Center of Future Science, College of Chemistry Jilin University Changchun ChinaState Key Laboratory of Inorganic Synthesis and Preparative Chemistry, International Center of Future Science, College of Chemistry Jilin University Changchun ChinaState Key Laboratory of Inorganic Synthesis and Preparative Chemistry, International Center of Future Science, College of Chemistry Jilin University Changchun ChinaState Key Laboratory of Inorganic Synthesis and Preparative Chemistry, International Center of Future Science, College of Chemistry Jilin University Changchun ChinaState Key Laboratory of Inorganic Synthesis and Preparative Chemistry, International Center of Future Science, College of Chemistry Jilin University Changchun ChinaState Key Laboratory of Inorganic Synthesis and Preparative Chemistry, International Center of Future Science, College of Chemistry Jilin University Changchun ChinaState Key Laboratory of Inorganic Synthesis and Preparative Chemistry, International Center of Future Science, College of Chemistry Jilin University Changchun ChinaState Key Laboratory of Inorganic Synthesis and Preparative Chemistry, International Center of Future Science, College of Chemistry Jilin University Changchun ChinaAbstract Electrocatalytic reduction of nitrate pollutants to produce ammonia offers an effective approach to realizing the artificial nitrogen cycle and replacing the energy‐intensive Haber‐Bosch process. Nitrite is an important intermediate product in the reduction of nitrate to ammonia. Therefore, the mechanism of converting nitrite into ammonia warrants further investigation. Molecular cobalt catalysts are regarded as promising for nitrite reduction reactions (NO2−RR). However, designing and controlling the coordination environment of molecular catalysts is crucial for studying the mechanism of NO2−RR and catalyst design. Herein, we develop a molecular platform of cobalt porphyrin with three coordination microenvironments (Co‐N3X1, X = N, O, S). Electrochemical experiments demonstrate that cobalt porphyrin with O coordination (CoOTPP) exhibits the lowest onset potential and the highest activity for NO2−RR in ammonia production. Under neutral, non‐buffered conditions over a wide potential range (−1.0 to −1.5 V versus AgCl/Ag), the Faradaic efficiency of nearly 90% for ammonia was achieved and reached 94.5% at −1.4 V versus AgCl/Ag, with an ammonia yield of 6,498 μg h−1 and a turnover number of 22,869 at −1.5 V versus AgCl/Ag. In situ characterization and density functional theory calculations reveal that modulating the coordination environment alters the electron transfer mode of the cobalt active center and the charge redistribution caused by the break of the ligand field. Therefore, this results in enhanced electrochemical activity for NO2−RR in ammonia production. This study provides valuable guidance for designing adjustments to the coordination environment of molecular catalysts to enhance catalytic activity.https://doi.org/10.1002/cey2.657coordination environmentelectrocatalytic nitrite reductionheterogeneous catalysismolecular catalyst |
| spellingShingle | Jingwei Han Hai Sun Fengkun Tian Wenwen Zhang Zonghang Zhang Ping She Jun‐Sheng Qin Heng Rao Modulating the coordination environment of cobalt porphyrins for enhanced electrochemical nitrite reduction to ammonia Carbon Energy coordination environment electrocatalytic nitrite reduction heterogeneous catalysis molecular catalyst |
| title | Modulating the coordination environment of cobalt porphyrins for enhanced electrochemical nitrite reduction to ammonia |
| title_full | Modulating the coordination environment of cobalt porphyrins for enhanced electrochemical nitrite reduction to ammonia |
| title_fullStr | Modulating the coordination environment of cobalt porphyrins for enhanced electrochemical nitrite reduction to ammonia |
| title_full_unstemmed | Modulating the coordination environment of cobalt porphyrins for enhanced electrochemical nitrite reduction to ammonia |
| title_short | Modulating the coordination environment of cobalt porphyrins for enhanced electrochemical nitrite reduction to ammonia |
| title_sort | modulating the coordination environment of cobalt porphyrins for enhanced electrochemical nitrite reduction to ammonia |
| topic | coordination environment electrocatalytic nitrite reduction heterogeneous catalysis molecular catalyst |
| url | https://doi.org/10.1002/cey2.657 |
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