Degradation Mechanisms of Platinum Group Metal‐Free Oxygen Reduction Reaction Catalyst based on Iron Phthalocyanine
Abstract Platinum group metal‐free catalysts have been considered the most promising alternative for platinum‐based catalysts for the oxygen reduction reaction in fuel cells. Despite the significant advancement made in activity, their viability as fuel cell catalysts is still questionable due to the...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley-VCH
2023-04-01
|
| Series: | ChemElectroChem |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/celc.202300042 |
| _version_ | 1797807356283715584 |
|---|---|
| author | Hilah C. Honig Prof. Dr. Lior Elbaz |
| author_facet | Hilah C. Honig Prof. Dr. Lior Elbaz |
| author_sort | Hilah C. Honig |
| collection | DOAJ |
| description | Abstract Platinum group metal‐free catalysts have been considered the most promising alternative for platinum‐based catalysts for the oxygen reduction reaction in fuel cells. Despite the significant advancement made in activity, their viability as fuel cell catalysts is still questionable due to their low durability. So far, deciphering the degradation mechanisms of this class of catalysts has been hampered by their undefined structure. Herein, we used a molecular model catalyst, iron‐phthalocyanine, featuring Fe−N4 active sites with resemblance to those in the more active Fe−N−C catalysts, and studied their degradation mechanisms. Based on X‐ray photoelectron spectroscopy and the electrochemical measurements, three main demetallation processes were identified: at potentials higher than 0.65 V vs. RHE, where the metal center is Fe3+, an electrochemical oxidation of the ligand ring is occurring, between 0.6 and 0.2 V vs. RHE, Fenton reagents are produced and attack the catalyst and support, and at lower voltages, where peroxide is produced by the catalyst and the carbon support. The combination of the different iron oxidation states together with the oxygen species directs to different degradation mechanisms. The decay rates obtained in the stability measurements establish what is mainly causing the loss of activity. Thereby, this model molecule can aid in understanding the degradation mechanisms of other platinum group metal‐free oxygen reduction reaction catalysts. |
| first_indexed | 2024-03-13T06:21:21Z |
| format | Article |
| id | doaj.art-1536e054d1164182bf02c6cf7fc31242 |
| institution | Directory Open Access Journal |
| issn | 2196-0216 |
| language | English |
| last_indexed | 2024-03-13T06:21:21Z |
| publishDate | 2023-04-01 |
| publisher | Wiley-VCH |
| record_format | Article |
| series | ChemElectroChem |
| spelling | doaj.art-1536e054d1164182bf02c6cf7fc312422023-06-09T18:22:04ZengWiley-VCHChemElectroChem2196-02162023-04-01107n/an/a10.1002/celc.202300042Degradation Mechanisms of Platinum Group Metal‐Free Oxygen Reduction Reaction Catalyst based on Iron PhthalocyanineHilah C. Honig0Prof. Dr. Lior Elbaz1Chemistry Department Bar-Ilan University Ramat-Gan 529002 IsraelChemistry Department Bar-Ilan University Ramat-Gan 529002 IsraelAbstract Platinum group metal‐free catalysts have been considered the most promising alternative for platinum‐based catalysts for the oxygen reduction reaction in fuel cells. Despite the significant advancement made in activity, their viability as fuel cell catalysts is still questionable due to their low durability. So far, deciphering the degradation mechanisms of this class of catalysts has been hampered by their undefined structure. Herein, we used a molecular model catalyst, iron‐phthalocyanine, featuring Fe−N4 active sites with resemblance to those in the more active Fe−N−C catalysts, and studied their degradation mechanisms. Based on X‐ray photoelectron spectroscopy and the electrochemical measurements, three main demetallation processes were identified: at potentials higher than 0.65 V vs. RHE, where the metal center is Fe3+, an electrochemical oxidation of the ligand ring is occurring, between 0.6 and 0.2 V vs. RHE, Fenton reagents are produced and attack the catalyst and support, and at lower voltages, where peroxide is produced by the catalyst and the carbon support. The combination of the different iron oxidation states together with the oxygen species directs to different degradation mechanisms. The decay rates obtained in the stability measurements establish what is mainly causing the loss of activity. Thereby, this model molecule can aid in understanding the degradation mechanisms of other platinum group metal‐free oxygen reduction reaction catalysts.https://doi.org/10.1002/celc.202300042electrocatalysisfuel cellsmolecular catalystsoxygen reduction reactionphthalocyanines |
| spellingShingle | Hilah C. Honig Prof. Dr. Lior Elbaz Degradation Mechanisms of Platinum Group Metal‐Free Oxygen Reduction Reaction Catalyst based on Iron Phthalocyanine ChemElectroChem electrocatalysis fuel cells molecular catalysts oxygen reduction reaction phthalocyanines |
| title | Degradation Mechanisms of Platinum Group Metal‐Free Oxygen Reduction Reaction Catalyst based on Iron Phthalocyanine |
| title_full | Degradation Mechanisms of Platinum Group Metal‐Free Oxygen Reduction Reaction Catalyst based on Iron Phthalocyanine |
| title_fullStr | Degradation Mechanisms of Platinum Group Metal‐Free Oxygen Reduction Reaction Catalyst based on Iron Phthalocyanine |
| title_full_unstemmed | Degradation Mechanisms of Platinum Group Metal‐Free Oxygen Reduction Reaction Catalyst based on Iron Phthalocyanine |
| title_short | Degradation Mechanisms of Platinum Group Metal‐Free Oxygen Reduction Reaction Catalyst based on Iron Phthalocyanine |
| title_sort | degradation mechanisms of platinum group metal free oxygen reduction reaction catalyst based on iron phthalocyanine |
| topic | electrocatalysis fuel cells molecular catalysts oxygen reduction reaction phthalocyanines |
| url | https://doi.org/10.1002/celc.202300042 |
| work_keys_str_mv | AT hilahchonig degradationmechanismsofplatinumgroupmetalfreeoxygenreductionreactioncatalystbasedonironphthalocyanine AT profdrliorelbaz degradationmechanismsofplatinumgroupmetalfreeoxygenreductionreactioncatalystbasedonironphthalocyanine |