Intrinsic properties of nanoparticulate Ir-based catalysts for oxygen evolution reaction by AC voltammetry

Vodeb, Ožbej; Lončar, Anja; Bele, Marjan; Hrnjić, Armin; Jovanovič, Primož; Gaberšček, Miran; Hodnik, Nejc

doi:10.1016/j.electacta.2023.142882

Cited by 2 publications

(4 citation statements)

References 31 publications

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“…The potential influence of charge contributions from the backing electrode on the precision of the Ir ECSA assessments is an important consideration. Combining this method in combination with EIS could provide a more distinct differentiation between double-layer and pseudocapacitive charge . It is also important to reference the recent study by Lončar et al, which highlighted that the EIS method is not applicable for supported Ir-based nanopowders.…”

Section: Resultsmentioning

confidence: 99%

“…Combining this method in combination with EIS could provide a more distinct differentiation between double-layer and pseudocapacitive charge. 97 It is also important to reference the recent study by Loncǎr et al, 98 which highlighted that the EIS method is not applicable for supported Ir-based nanopowders. Yet, given the potential insights provided by this method, its further exploration and potential applicability in future measurements are essential.…”

Section: Redeposition Mechanism Of the Au Backing Electrodementioning

confidence: 99%

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Standardizing OER Electrocatalyst Benchmarking in Aqueous Electrolytes: Comprehensive Guidelines for Accelerated Stress Tests and Backing Electrodes

Zlatar,

Escalera-López,

Rodríguez

et al. 2023

ACS Catal.

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The scarcity of iridium, needed to catalyze the sluggish oxygen evolution reaction (OER), hinders large-scale hydrogen production with proton exchange membrane water electrolyzers (PEMWEs). Crucial steps require reducing its loading while improving its overall activity and stability. Despite knowledge transfer challenges, cost and time constraints still favor aqueous model systems (AMSs) over real devices for the OER electrocatalyst testing. During AMS testing, benchmarking strategies such as accelerated stress tests (ASTs) aim at improving catalyst lifetime estimation compared to constant current loads. This study systematically evaluates a commercial Ir catalyst by modifying both AST parameters and the employed backing electrodes to examine their impact on activity−stability relationships. A comprehensive set of spectroscopy and microscopy techniques, including in situ inductively coupled plasma mass spectrometry, is employed to monitor Ir and backing electrode modifications. Our findings demonstrate that the choice of both lower potential limit (LPL) in ASTs and backing electrode significantly influences the estimation of Ir-based electrocatalysts' activity and stability. Unique degradation mechanisms, such as passivation, redeposition on active sites, and contribution to the OER, were observed for different backing electrodes at varying LPLs. These results emphasize the importance of optimizing parameters and electrode selection in ASTs to accurately assess the electrocatalyst performance. Furthermore, they establish the foundation for developing relevant standardized test protocols, enabling the cost-effective development of high-performance catalysts for PEMWE applications.

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Section: Resultsmentioning

confidence: 99%

Section: Redeposition Mechanism Of the Au Backing Electrodementioning

confidence: 99%

Standardizing OER Electrocatalyst Benchmarking in Aqueous Electrolytes: Comprehensive Guidelines for Accelerated Stress Tests and Backing Electrodes

Zlatar,

Escalera-López,

Rodríguez

et al. 2023

ACS Catal.

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show abstract

“…Their results confirm the estimated magnitudes of the rate constants found in the work of Bonke et al highlighting the importance of such endeavors. Vodeb et al followed a similar methodology and gained valuable insights on the catalysis of OER in acidic media with precious metal catalysts . They compared between different Ir-based catalysts, probing the kinetic and thermodynamic reaction parameters by comparing the higher harmonic components to a detailed microkinetic model enabling them to draw mechanistic conclusions on the differences in activity between the catalysts.…”

Section: Analysis Of Electrocatalysts Using Ftacvmentioning

confidence: 99%

“…Vodeb et al followed a similar methodology and gained valuable insights on the catalysis of OER in acidic media with precious metal catalysts. 103 They compared between different Ir-based catalysts, probing the kinetic and thermodynamic reaction parameters by comparing the higher harmonic components to a detailed microkinetic model enabling them to draw mechanistic conclusions on the differences in activity between the catalysts. Recently, Snitkoff-Sol et al investigated the ORR with a PGM-free catalyst.…”

Section: Determination Of Reaction Parameters Of the Redox Reaction O...mentioning

confidence: 99%

Fourier-Transformed Alternating Current Voltammetry (FTacV) for Analysis of Electrocatalysts

Snitkoff-Sol,

Bond,

Elbaz

2024

ACS Catal.

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Electrocatalysts play a critical role in energy technologies, but the development of active, efficient, and durable catalysts is impeded by the lack of methodologies to deconvolute the complex interplay between various aspects influencing the activity of the catalysts, e.g., the number of active sites, turnover frequency, and the reaction pathways. Fourier-transformed alternating current voltammetry (FTacV) is an emerging tool for the analysis of electroactive species and has been successfully applied to a variety of reactions such as the oxygen reduction reaction, oxygen evolution reaction, carbon dioxide reduction reaction, hydrogen evolution reaction, and hydrogen oxidation reaction. The harmonics generated from FTacV measurements neatly detect underlaying processes not visible by other, more commonly employed techniques for analysis of electrocatalysts, such as the rotating disc electrode and dc voltammetry. The harmonic components enable separating overlapping processes based on differences in kinetics or linearity of response. This paper presents a review of FTacV applied for the analysis of electrocatalysts. It highlights the importance of determining the electrochemically active site density (EASD) to decipher the intrinsic activity of a catalyst and discusses the use of FTacV in dynamic determination of the EASD over the course of a catalyst's working life, as well as the use of FTacV to understand intricate catalytic processes.

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Intrinsic properties of nanoparticulate Ir-based catalysts for oxygen evolution reaction by AC voltammetry

Cited by 2 publications

References 31 publications

Standardizing OER Electrocatalyst Benchmarking in Aqueous Electrolytes: Comprehensive Guidelines for Accelerated Stress Tests and Backing Electrodes

Standardizing OER Electrocatalyst Benchmarking in Aqueous Electrolytes: Comprehensive Guidelines for Accelerated Stress Tests and Backing Electrodes

Fourier-Transformed Alternating Current Voltammetry (FTacV) for Analysis of Electrocatalysts

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