The Local Coordination Effects on the Reactivity and Speciation of Active Sites in Graphene-Embedded Single-Atom Catalysts over Wide pH and Potential Range
Understanding the catalytic performance of different materials is of crucial importance for achieving further technological advancements. This especially relates to the behaviors of different classes of catalysts under operating conditions. Here, we analyzed the effects of local coordination of meta...
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| Format: | Article |
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MDPI AG
2022-12-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/12/23/4309 |
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| author | Milica S. Ritopečki Ana S. Dobrota Natalia V. Skorodumova Igor A. Pašti |
| author_facet | Milica S. Ritopečki Ana S. Dobrota Natalia V. Skorodumova Igor A. Pašti |
| author_sort | Milica S. Ritopečki |
| collection | DOAJ |
| description | Understanding the catalytic performance of different materials is of crucial importance for achieving further technological advancements. This especially relates to the behaviors of different classes of catalysts under operating conditions. Here, we analyzed the effects of local coordination of metal centers (Mn, Fe, Co) in graphene-embedded single-atom catalysts (SACs). We started with well-known M@N<sub>4</sub>-graphene catalysts and systematically replaced nitrogen atoms with oxygen or sulfur atoms to obtain M@O<sub>x</sub>N<sub>y</sub>-graphene and M@S<sub>x</sub>N<sub>y</sub>-graphene SACs (x + y = 4). We show that local coordination strongly affects the electronic structure and reactivity towards hydrogen and oxygen species. However, stability is even more affected. Using the concept of Pourbaix plots, we show that the replacement of nitrogen atoms in metal coordinating centers with O or S destabilized the SACs towards dissolution, while the metal centers were easily covered by O and OH, acting as additional ligands at high anodic potentials and high pH values. Thus, not only should local coordination be considered in terms of the activity of SACs, but it is also necessary to consider its effects on the speciation of SAC active centers under different potentials and pH conditions. |
| first_indexed | 2024-03-09T17:37:32Z |
| format | Article |
| id | doaj.art-3f46b2a4ccb64952aeedef6f19730807 |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-09T17:37:32Z |
| publishDate | 2022-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-3f46b2a4ccb64952aeedef6f197308072023-11-24T11:48:52ZengMDPI AGNanomaterials2079-49912022-12-011223430910.3390/nano12234309The Local Coordination Effects on the Reactivity and Speciation of Active Sites in Graphene-Embedded Single-Atom Catalysts over Wide pH and Potential RangeMilica S. Ritopečki0Ana S. Dobrota1Natalia V. Skorodumova2Igor A. Pašti3University of Belgrade—Faculty of Physical Chemistry, Studentski trg 12-16, 11158 Belgrade, SerbiaUniversity of Belgrade—Faculty of Physical Chemistry, Studentski trg 12-16, 11158 Belgrade, SerbiaDepartment of Materials Science and Engineering, School of Industrial Engineering and Management, KTH—Royal Institute of Technology, Brinellvägen 23, 100 44 Stockholm, SwedenUniversity of Belgrade—Faculty of Physical Chemistry, Studentski trg 12-16, 11158 Belgrade, SerbiaUnderstanding the catalytic performance of different materials is of crucial importance for achieving further technological advancements. This especially relates to the behaviors of different classes of catalysts under operating conditions. Here, we analyzed the effects of local coordination of metal centers (Mn, Fe, Co) in graphene-embedded single-atom catalysts (SACs). We started with well-known M@N<sub>4</sub>-graphene catalysts and systematically replaced nitrogen atoms with oxygen or sulfur atoms to obtain M@O<sub>x</sub>N<sub>y</sub>-graphene and M@S<sub>x</sub>N<sub>y</sub>-graphene SACs (x + y = 4). We show that local coordination strongly affects the electronic structure and reactivity towards hydrogen and oxygen species. However, stability is even more affected. Using the concept of Pourbaix plots, we show that the replacement of nitrogen atoms in metal coordinating centers with O or S destabilized the SACs towards dissolution, while the metal centers were easily covered by O and OH, acting as additional ligands at high anodic potentials and high pH values. Thus, not only should local coordination be considered in terms of the activity of SACs, but it is also necessary to consider its effects on the speciation of SAC active centers under different potentials and pH conditions.https://www.mdpi.com/2079-4991/12/23/4309single-atom catalystsgrapheneactivityreactivitystabilityPourbaix plots |
| spellingShingle | Milica S. Ritopečki Ana S. Dobrota Natalia V. Skorodumova Igor A. Pašti The Local Coordination Effects on the Reactivity and Speciation of Active Sites in Graphene-Embedded Single-Atom Catalysts over Wide pH and Potential Range Nanomaterials single-atom catalysts graphene activity reactivity stability Pourbaix plots |
| title | The Local Coordination Effects on the Reactivity and Speciation of Active Sites in Graphene-Embedded Single-Atom Catalysts over Wide pH and Potential Range |
| title_full | The Local Coordination Effects on the Reactivity and Speciation of Active Sites in Graphene-Embedded Single-Atom Catalysts over Wide pH and Potential Range |
| title_fullStr | The Local Coordination Effects on the Reactivity and Speciation of Active Sites in Graphene-Embedded Single-Atom Catalysts over Wide pH and Potential Range |
| title_full_unstemmed | The Local Coordination Effects on the Reactivity and Speciation of Active Sites in Graphene-Embedded Single-Atom Catalysts over Wide pH and Potential Range |
| title_short | The Local Coordination Effects on the Reactivity and Speciation of Active Sites in Graphene-Embedded Single-Atom Catalysts over Wide pH and Potential Range |
| title_sort | local coordination effects on the reactivity and speciation of active sites in graphene embedded single atom catalysts over wide ph and potential range |
| topic | single-atom catalysts graphene activity reactivity stability Pourbaix plots |
| url | https://www.mdpi.com/2079-4991/12/23/4309 |
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