Beware of cyclic voltammetry! Measurement artefact in accelerated stress test of fuel cell cathode revealed by operando X-ray diffraction

Chattot, Raphaël; Mirolo, Marta; Martens, Isaac; Kumar, Kavita; Martin, Vincent; Gasmi, Amir; Dubau, Laëtitia; Maillard, Frédéric; Castanheira, Luis; Drnec, Jakub

doi:10.1016/j.jpowsour.2022.232345

Cited by 12 publications

(13 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, Chattot et al investigated the effect of potential cycling to low potential after the application of an accelerated stress test protocol. Their results demonstrate that the observed agglomeration of catalyst particles is induced by cycling to low potential rather than a consequence of the performed stress protocol [63]. Therefore, special care has to be taken, when ECSA methods are performed after or in between stress tests.…”

Section: Which Methods Should Be Chosen For Ecsa Determination?mentioning

confidence: 97%

Comparison of methods to determine electrocatalysts’ surface area in gas diffusion electrode setups: a case study on Pt/C and PtRu/C

Röttcher

Ku²,

Minichová³

et al. 2023

J. Phys. Energy

View full text Add to dashboard Cite

In recent years, gas diffusion electrode half-cell setups have attained increasing attention bridging the gap between fundamental and applied fuel cell research. They allow quick and reliable evaluation of fuel cell catalyst layers and provide a unique possibility to screen different electrocatalysts at close to real experimental conditions. However, benchmarking electrocatalysts’ intrinsic activity and stability is impossible without knowing their electrochemical active surface area (ECSA). In this work, we compare and contrast three methods for the determination of the ECSA: (a) underpotential deposition of hydrogen (Hupd); (b) CO-stripping; and (c) underpotential deposition of copper (Cuupd) in acidic and alkaline electrolytes, using representative electrocatalysts for fuel cell applications (Pt and PtRu-alloys supported on carbon). We demonstrate that, while all methods can be used in gas diffusion electrode setups, CO-stripping is the most convenient and reliable. Additionally, the application of Cuupd offers the possibility to derive the atomic surface ratio in PtRu-alloy catalysts. By discussing the advantages of each method, we hope to guide future research in accurately determining surface area and, hence, the intrinsic performance of realistic catalyst layers.

show abstract

Section: Which Methods Should Be Chosen For Ecsa Determination?mentioning

confidence: 97%

Comparison of methods to determine electrocatalysts’ surface area in gas diffusion electrode setups: a case study on Pt/C and PtRu/C

Röttcher

Ku²,

Minichová³

et al. 2023

J. Phys. Energy

View full text Add to dashboard Cite

show abstract

“…Beyond the oxidation-dependent size dynamics, WAXS has also been extensively used to investigate the long-term stability of Pt-based catalysts in the environment of electrochemical cells. Taking the nanoparticles’ coherent domain size increase as an indicator of catalyst degradation, the influence of the catalyst support material chemistry such as doped metal oxides − or carbon functionalization, , the initial particles ’size distribution, , the liquid vs solid electrolyte, the upper potential limit during accelerated cycling, or the post-mortem cyclic voltammetry experiment on the material stability were investigated by means of in situ WAXS.…”

Section: Electrocatalysismentioning

confidence: 99%

“…Furthermore, Chattot et al also characterized in operando the anomalous aging of the Pt catalyst after accelerated stress test (AST). 462 the AST's low potential limit, which removes the surface oxygen from oxophilic sites and causes sintering of the catalyst particles and increase of the electrochemical surface area. These findings are only obtainable by performing operando measurements in industrially relevant, high-performance devices.…”

Section: Electrocatalytic Devicesmentioning

confidence: 99%

“…From the WAXS data the size of coherent domains, i.e., the individual crystallites, was determined and the SAXS data provided the size of aggregated particles, given that aggregation occurs during the aging of the catalyst. Furthermore, Chattot et al also characterized in operando the anomalous aging of the Pt catalyst after accelerated stress test (AST) . Interestingly, the catalyst fully degrades only when the potential is swept below the AST’s low potential limit, which removes the surface oxygen from oxophilic sites and causes sintering of the catalyst particles and increase of the electrochemical surface area.…”

Section: Electrocatalysismentioning

confidence: 99%

See 1 more Smart Citation

In Situ and Operando X-ray Scattering Methods in Electrochemistry and Electrocatalysis

Magnussen,

Drnec,

Qiu

et al. 2024

Chem. Rev.

Self Cite

View full text Add to dashboard Cite

show abstract

“…[92] It has e.g been shown that CVs performed after the completion of a typical AST of a PEMFC cause a more coherent domain size increase in the Pt catalyst than the AST itself. [93] This measurement-induced artifact can lead to misinterpretations of catalyst performance, which appears to be less stable. One should carefully choose the operational window in both oxidating and reducing potential windows, as both oxidation and reduction can induce structural changes in the catalyst.…”

Section: Mitigating Radiation Damagementioning

confidence: 99%

Shedding Light on Electrocatalysts: Practical Considerations for Operando Studies with High‐Energy X‐Rays

Pittkowski

2024

ChemElectroChem

View full text Add to dashboard Cite

Operando studies using high‐energy X‐rays from synchrotron sources are essential for unraveling the complex material transformation that electrocatalysts undergo under operating conditions. This article explores key considerations to perform these experiments and the insights gained from such studies on nanostructured electrocatalysts. Critical factors include optimizing electrochemical performance while obtaining high‐quality X‐ray signals, which often require compromises. The electrochemical operando cell design is crucial, and several different cells are discussed here. Working electrode geometries parallel to the X‐ray beam, probed with a microfocused beam, are emerging as promising solutions for realistic electrochemical performance in operando cells. Careful attention must also be paid to the electrochemical measuring conditions, electrode loading, and beam damage to ensure reliable experiments. When carefully performed and by combining multiple characterization techniques, operando studies with high‐energy X‐rays offer the unique possibility to fully understand the structure of the active electrocatalyst.

show abstract

Beware of cyclic voltammetry! Measurement artefact in accelerated stress test of fuel cell cathode revealed by operando X-ray diffraction

Cited by 12 publications

References 32 publications

Comparison of methods to determine electrocatalysts’ surface area in gas diffusion electrode setups: a case study on Pt/C and PtRu/C

Comparison of methods to determine electrocatalysts’ surface area in gas diffusion electrode setups: a case study on Pt/C and PtRu/C

In Situ and Operando X-ray Scattering Methods in Electrochemistry and Electrocatalysis

Shedding Light on Electrocatalysts: Practical Considerations for Operando Studies with High‐Energy X‐Rays

Contact Info

Product

Resources

About