In-situ detection of active sites for carbon-based bifunctional oxygen reduction and evolution catalysis

Haid, Richard W.; Kluge, Regina M.; Schmidt, Thorsten O.; Bandarenka, Aliaksandr S.

doi:10.1016/j.electacta.2021.138285

Cited by 18 publications

(25 citation statements)

References 61 publications

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“…It is believed that pure “defect‐free” carbon materials such as carbon blacks, carbon nanotubes, and graphene possess insufficient ORR activity due to the reaction proceeding via a two‐electron pathway [44,45] . In many studies, the active sites of pure carbon‐based materials have been assigned to step and defect sites in the case of the ORR [46–53] . The OER active sites have been less studied, which may be due to carbon corrosion interfering with the catalysis [37,53] .…”

Section: Extended Surfacesmentioning

confidence: 99%

“…The OER active sites have been less studied, which may be due to carbon corrosion interfering with the catalysis [37,53] . Still, literature studies conclude that defects such as deviations in the ring structure and step edges are beneficial for the OER [11,51,53] . As an example, Yao and co‐workers studied the OER and ORR activities of defective graphite to understand the underlying principles [11] .…”

Section: Extended Surfacesmentioning

confidence: 99%

“…As an example, Haid et al . recently confirmed step edges and defects as active sites on graphite materials for both OER and ORR [51] . The authors used an in‐situ scanning probe method, which is introduced in section 7.…”

Section: Extended Surfacesmentioning

confidence: 99%

“…An additional technique to determine the position of active sites in‐situ is noise analysis in electrochemical scanning tunneling microscopy (n‐EC‐STM) [24,51,134,154–157] . Unlike the aforementioned techniques, the method benefits from the outstanding resolution of STM, and was proven to resolve the surface down to the atomic scale [158] .…”

Section: In‐situ Active Site Detection Techniquesmentioning

confidence: 99%

“…The resulting STM profile (purple) shows that active sites can be identified by the noise spikes while the rest of the surface is traced with a stable, noise‐free signal. In Figure 15b, the method is demonstrated for HOPG in an alkaline medium (0.1 M KOH) for ORR and OER [51] . We investigate a surface structure consisting of steps and terraces, which are clearly visible while the reactions are ‘off’ (middle in Figure 15b).…”

Section: In‐situ Active Site Detection Techniquesmentioning

confidence: 99%

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A Review on Experimental Identification of Active Sites in Model Bifunctional Electrocatalytic Systems for Oxygen Reduction and Evolution Reactions

et al. 2021

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Efficient electrocatalysis of the oxygen reduction (ORR) and evolution (OER) reactions is essential in numerous renewable energy conversion systems, such as fuel cells, metal‐air batteries, and water electrolyzers. Design and optimization of electrocatalytic materials for such systems primarily rely on understanding the nature of active centers on the catalyst surface. This review focuses on several important aspects of the experimental identification of active sites on various model bifunctional ORR/OER electrocatalytic surfaces. Applications of the state‐of‐the‐art experimental techniques are analyzed. In addition, approaches to investigate and understand the influence of some supporting electrolyte components on the ORR and OER activities are discussed.

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Section: Extended Surfacesmentioning

confidence: 99%

Section: Extended Surfacesmentioning

confidence: 99%

Section: Extended Surfacesmentioning

confidence: 99%

Section: In‐situ Active Site Detection Techniquesmentioning

confidence: 99%

Section: In‐situ Active Site Detection Techniquesmentioning

confidence: 99%

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A Review on Experimental Identification of Active Sites in Model Bifunctional Electrocatalytic Systems for Oxygen Reduction and Evolution Reactions

et al. 2021

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Scanning Tunneling Microscope

Zheng,

Luo,

Zheng

2024

Energy Storage Materials Characterization

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Metal Porphyrins as Single Site Catalyst Models Explored by Electrochemical Scanning Tunneling Microscopy: A New Perspective in Electrocatalysis

Facchin

Durante

2022

Advanced Sustainable Systems

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M–N–C materials featuring M–Nx single site catalysts, where for example M = Co, Mg, or Fe coordinating x atoms of nitrogen, have been intensely investigated as promising candidates to replace Pt group metals in a variety of electrocatalytic reactions, for example in the O2 reduction reactions (ORR). However, despite the recent emerging of atomic resolution techniques, there is still a lack of understanding of the precise configuration of the M–Nx single site. For example, metal porphyrins are known to act as catalysts for O2 and they are indeed good model systems for mimicking M–N4 sites. In particular, it would be of interest to gain more information on the precise dynamic of the catalytic process at atomic scale, especially in an electrochemical environment, i.e., at electrode/electrolyte interphase. An approach that is becoming more and more consolidated is to combine the information coming from electrochemistry and scanning tunneling microscopy techniques in electrochemical scanning tunneling microscopy (EC‐STM) and the result is that a precise dynamic of the catalytic site at atomic scale can be investigated. This review aims to emphasize the main results and advances of EC‐STM in investigating small molecule electrocatalysis and specifically O2 reduction at metal porphyrins M–N4 model system.

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In-situ detection of active sites for carbon-based bifunctional oxygen reduction and evolution catalysis

Cited by 18 publications

References 61 publications

A Review on Experimental Identification of Active Sites in Model Bifunctional Electrocatalytic Systems for Oxygen Reduction and Evolution Reactions

A Review on Experimental Identification of Active Sites in Model Bifunctional Electrocatalytic Systems for Oxygen Reduction and Evolution Reactions

Scanning Tunneling Microscope

Metal Porphyrins as Single Site Catalyst Models Explored by Electrochemical Scanning Tunneling Microscopy: A New Perspective in Electrocatalysis

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