Evaluating the stability of Ir single atom and Ru atomic cluster oxygen evolution reaction electrocatalysts

Zlatar, Matej; Nater, Darryl; Escalera‐López, Daniel; Joy, R. Mary; Pobedinskas, Paulius; Haenen, Ken; Copéret, Christophe; Cherevko, Serhiy

doi:10.1016/j.electacta.2023.141982

Cited by 29 publications

(9 citation statements)

References 98 publications

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“…With different substrate materials supporting the RuO 2 films, the Δ E varies with a range of ∼150 mV (Figure a), while the stability numbers remain the same (Figure b). Similar observations were also reported for some powder catalyst , drop-casted on various substrates. This result indicates that the Δ E correlates with the selected substrate material, independent of the catalyst (Figure S6d).…”

Section: Resultsmentioning

confidence: 99%

Benchmarking Electrocatalyst Stability for Acidic Oxygen Evolution Reaction: The Crucial Role of Dissolved Ion Concentration

Wei,

Wang,

Otani

et al. 2023

ACS Catal.

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Developing robust catalysts for the acidic oxygen evolution reaction (OER) is critical for large-scale implementation of proton exchange membrane (PEM) water electrolyzers. A promising strategy is to stabilize Ru-based catalysts by suppressing Ru dissolution, which requires knowledge of RuO2 stability. This work explores the influences on measuring the stability number of RuO2 and presents a comprehensive analysis and comparison of its stability with other electrocatalysts. We observe that RuO2 shows relatively higher stability in electrolytes with a confined working volume because of the Nernst shift caused by the concentration buildup of dissolved Ru. The stability number of RuO2 has a negligible dependence on the measurement duration, applied current density, Nafion content, and substrate materials. Furthermore, we analyze the effects of these factors on other typical OER catalysts and identify that the concentration of dissolved ions is key to understanding the stability number measured by different electrochemical cells and the claimed excellent stability of non-noble catalysts reported in the literature. In addition, the comparison of the stability number and intrinsic activity of RuO2, IrO2, and non-noble catalysts demonstrates that RuO2 is at least 2 orders of magnitude less stable but also 10-fold more active than IrO2 and that noble catalysts significantly outperform non-noble catalysts in terms of both stability and activity, posing a grand challenge in developing robust OER catalysts. This work establishes a baseline for enhancing the stability of Ru-based OER catalysts in acidic liquid cells and provides a valuable reference for PEM water electrolyzers.

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Section: Resultsmentioning

confidence: 99%

Benchmarking Electrocatalyst Stability for Acidic Oxygen Evolution Reaction: The Crucial Role of Dissolved Ion Concentration

Wei,

Wang,

Otani

et al. 2023

ACS Catal.

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“…150 nm thick BDD thin films were grown in 2 h on polished single crystal (100) silicon substrates (7 mm × 7 mm) at a temperature of 725 °C. For more detailed information about the procedure, the reader is referred to our previous publication . Metallic Ir thin films were magnetron sputtered by PVD on 100 mm diameter, single-side polished (100) Si wafers with a 500 nm wet thermal SiO 2 barrier layer.…”

Section: Methodsmentioning

confidence: 99%

“…For more detailed information about the procedure, the reader is referred to our previous publication. 42 Metallic Ir thin films were magnetron sputtered by PVD on 100 mm diameter, single-side polished (100) Si wafers with a 500 nm wet thermal SiO 2 barrier layer. Depositions were carried out in a loadlocked UHV chamber having a confocal cathode to substrate configuration (CMS 600/400 LIN, DCA Instruments, Finland), using substrate rotation to achieve better than 1% thickness uniformity.…”

Section: Methodsmentioning

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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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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“…[70] As prospective OER electrocatalysts, isolated iridium atoms have also performed well. [71][72][73] For instance, through one-step reduction procedure, a three-dimensional (3D) amorphous nanowire@nanosheets (NW@NSs) of NiFeIr x /Ni coreshell structure was reported. Isolated Iridium (Ir) atoms were anchored to a NiFe based core.…”

Section: Noble Metal Sacsmentioning

confidence: 99%

Catalyzing Sustainable Water Splitting with Single Atom Catalysts: Recent Advances

Alam,

Noor,

Iqbal

2024

The Chemical Record

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Electrochemical water splitting for sustainable hydrogen and oxygen production have shown enormous potentials. However, this method needs low‐cost and highly active catalysts. Traditional nano catalysts, while effective, have limits since their active sites are mostly restricted to the surface and edges, leaving interior surfaces unexposed in redox reactions. Single atom catalysts (SACs), which take advantage of high atom utilization and quantum size effects, have recently become appealing electrocatalysts. Strong interaction between active sites and support in SACs have considerably improved the catalytic efficiency and long‐term stability, outperforming their nano‐counterparts. This review‘s first section examines the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER). In the next section, SACs are categorized as noble metal, non‐noble metal, and bimetallic synergistic SACs. In addition, this review emphasizes developing methodologies for effective SAC design, such as mass loading optimization, electrical structure modulation, and the critical role of support materials. Finally, Carbon‐based materials and metal oxides are being explored as possible supports for SACs. Importantly, for the first time, this review opens a discussion on waste‐derived supports for single atom catalysts used in electrochemical reactions, providing a cost‐effective dimension to this vibrant research field. The well‐known design techniques discussed here may help in development of electrocatalysts for effective water splitting.

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Evaluating the stability of Ir single atom and Ru atomic cluster oxygen evolution reaction electrocatalysts

Cited by 29 publications

References 98 publications

Benchmarking Electrocatalyst Stability for Acidic Oxygen Evolution Reaction: The Crucial Role of Dissolved Ion Concentration

Benchmarking Electrocatalyst Stability for Acidic Oxygen Evolution Reaction: The Crucial Role of Dissolved Ion Concentration

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

Catalyzing Sustainable Water Splitting with Single Atom Catalysts: Recent Advances

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