Comparison of In Situ and Postsynthetic Formation of MOF-Carbon Composites as Electrocatalysts for the Alkaline Oxygen Evolution Reaction (OER)
Mixed-metal nickel-iron, Ni<sub>x</sub>Fe materials draw attention as affordable earth-abundant electrocatalysts for the oxygen evolution reaction (OER). Here, nickel and mixed-metal nickel-iron metal–organic framework (MOF) composites with the carbon materials ketjenblack (KB) or carbon...
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2025-01-01
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| author | Linda Sondermann Laura Maria Voggenauer Annette Vollrath Till Strothmann Christoph Janiak |
| author_facet | Linda Sondermann Laura Maria Voggenauer Annette Vollrath Till Strothmann Christoph Janiak |
| author_sort | Linda Sondermann |
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| description | Mixed-metal nickel-iron, Ni<sub>x</sub>Fe materials draw attention as affordable earth-abundant electrocatalysts for the oxygen evolution reaction (OER). Here, nickel and mixed-metal nickel-iron metal–organic framework (MOF) composites with the carbon materials ketjenblack (KB) or carbon nanotubes (CNT) were synthesized in situ in a one-pot solvothermal reaction. As a direct comparison to these in situ synthesized composites, the neat MOFs were postsynthetically mixed by grinding with KB or CNT, to generate physical mixture composites. The in situ and postsynthetic MOF/carbon samples were comparatively tested as (pre-)catalysts for the OER, and most of them outperformed the RuO<sub>2</sub> benchmark. Depending on the carbon material and metal ratio, the in situ or postsynthetic composites performed better, showing that the method to generate the composite can influence the OER activity. The best material Ni<sub>5</sub>Fe-CNT was synthesized in situ and achieved an overpotential (<i>η</i>) of 301 mV (RuO<sub>2</sub> <i>η</i> = 354 mV), a Tafel slope (<i>b</i>) of 58 mV/dec (RuO<sub>2</sub> <i>b</i> = 91 mV/dec), a charge transfer resistance (R<sub>ct</sub>) of 7 Ω (RuO<sub>2</sub> R<sub>ct</sub> = 39 Ω), and a faradaic efficiency (FE) of 95% (RuO<sub>2</sub> FE = 91%). Structural changes in the materials could be seen through a stability test in the alkaline electrolyte, and chronopotentiometry over 12 h showed that the derived electrocatalysts and RuO<sub>2</sub> have good stability. |
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| institution | Kabale University |
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| publishDate | 2025-01-01 |
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| spelling | doaj-art-0471555c184b40638446596b5396e8932025-01-24T13:43:07ZengMDPI AGMolecules1420-30492025-01-0130220810.3390/molecules30020208Comparison of In Situ and Postsynthetic Formation of MOF-Carbon Composites as Electrocatalysts for the Alkaline Oxygen Evolution Reaction (OER)Linda Sondermann0Laura Maria Voggenauer1Annette Vollrath2Till Strothmann3Christoph Janiak4Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, GermanyInstitut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, GermanyInstitut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, GermanyInstitut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, GermanyInstitut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, GermanyMixed-metal nickel-iron, Ni<sub>x</sub>Fe materials draw attention as affordable earth-abundant electrocatalysts for the oxygen evolution reaction (OER). Here, nickel and mixed-metal nickel-iron metal–organic framework (MOF) composites with the carbon materials ketjenblack (KB) or carbon nanotubes (CNT) were synthesized in situ in a one-pot solvothermal reaction. As a direct comparison to these in situ synthesized composites, the neat MOFs were postsynthetically mixed by grinding with KB or CNT, to generate physical mixture composites. The in situ and postsynthetic MOF/carbon samples were comparatively tested as (pre-)catalysts for the OER, and most of them outperformed the RuO<sub>2</sub> benchmark. Depending on the carbon material and metal ratio, the in situ or postsynthetic composites performed better, showing that the method to generate the composite can influence the OER activity. The best material Ni<sub>5</sub>Fe-CNT was synthesized in situ and achieved an overpotential (<i>η</i>) of 301 mV (RuO<sub>2</sub> <i>η</i> = 354 mV), a Tafel slope (<i>b</i>) of 58 mV/dec (RuO<sub>2</sub> <i>b</i> = 91 mV/dec), a charge transfer resistance (R<sub>ct</sub>) of 7 Ω (RuO<sub>2</sub> R<sub>ct</sub> = 39 Ω), and a faradaic efficiency (FE) of 95% (RuO<sub>2</sub> FE = 91%). Structural changes in the materials could be seen through a stability test in the alkaline electrolyte, and chronopotentiometry over 12 h showed that the derived electrocatalysts and RuO<sub>2</sub> have good stability.https://www.mdpi.com/1420-3049/30/2/208metal–organic frameworks (MOFs)electrocatalysisoxygen evolution reaction (OER)nickelironcarbon nanotubes |
| spellingShingle | Linda Sondermann Laura Maria Voggenauer Annette Vollrath Till Strothmann Christoph Janiak Comparison of In Situ and Postsynthetic Formation of MOF-Carbon Composites as Electrocatalysts for the Alkaline Oxygen Evolution Reaction (OER) Molecules metal–organic frameworks (MOFs) electrocatalysis oxygen evolution reaction (OER) nickel iron carbon nanotubes |
| title | Comparison of In Situ and Postsynthetic Formation of MOF-Carbon Composites as Electrocatalysts for the Alkaline Oxygen Evolution Reaction (OER) |
| title_full | Comparison of In Situ and Postsynthetic Formation of MOF-Carbon Composites as Electrocatalysts for the Alkaline Oxygen Evolution Reaction (OER) |
| title_fullStr | Comparison of In Situ and Postsynthetic Formation of MOF-Carbon Composites as Electrocatalysts for the Alkaline Oxygen Evolution Reaction (OER) |
| title_full_unstemmed | Comparison of In Situ and Postsynthetic Formation of MOF-Carbon Composites as Electrocatalysts for the Alkaline Oxygen Evolution Reaction (OER) |
| title_short | Comparison of In Situ and Postsynthetic Formation of MOF-Carbon Composites as Electrocatalysts for the Alkaline Oxygen Evolution Reaction (OER) |
| title_sort | comparison of in situ and postsynthetic formation of mof carbon composites as electrocatalysts for the alkaline oxygen evolution reaction oer |
| topic | metal–organic frameworks (MOFs) electrocatalysis oxygen evolution reaction (OER) nickel iron carbon nanotubes |
| url | https://www.mdpi.com/1420-3049/30/2/208 |
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