Systematic Investigation of Iridium-Based Bimetallic Thin Film Catalysts for the Oxygen Evolution Reaction in Acidic Media

Strickler, Alaina L.; Flores, Raul A.; King, Laurie A.; Nørskov, Jens K.; Bajdich, Michal; Jaramillo, Thomas F.

doi:10.1021/acsami.9b13697

Cited by 63 publications

(53 citation statements)

References 62 publications

(109 reference statements)

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“…Additionally, we have also added a kinetic OER volcano (dashed line) from Dickens et al 63 In general, the R-IrO 2 surfaces bind the OER intermediates relatively strongly, with theoretical limiting potentials of ∼1.8 V RHE (overpotential of 0.57 V RHE ) having the *O to *OOH potential limiting step, in agreement with previous theoretical studies. 59,64,65 The predicted overpotentials of our R-IrO 2 systems are also within the range of experimentally observed values (horizontal lines). 25,60 The surfaces of the three IrO 3 polymorphs have ∆G O -∆G OH values shifted to higher energies, indicative of overall weaker binding energetics (see also Figure S5).…”

Section: Electrochemical Oer Applicationsupporting

confidence: 85%

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Active Learning Accelerated Discovery of Stable Iridium-oxide Polymorphs for the Oxygen Evolution Reaction

Flores

Paolucci²,

Winther³

et al. 2020

Preprint

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The discovery of high-performing and stable materials for sustainable energy applications is a pressing goal in catalysis and materials science. Understanding the relationship between a material's structure and functionality is an important step in the process, such that viable polymorphs for a given chemical composition need to be identified. Machine-learning based surrogate models have the potential to accelerate the search for polymorphs that target specific applications. Herein, we report a readily generalizable active-learning (AL) accelerated algorithm for identification of electrochemically stable iridium-oxide polymorphs of IrO2 and IrO3. The search is coupled to a subsequent analysis of the electrochemical stability of the discovered structures for the acidic oxygen evolution reaction (OER). Structural candidates are generated by identifying all 956 structurally unique AB2 and AB3 prototypes in existing materials databases (more than 38000). Next, using an active learning approach we are able to find 196 IrO2 polymorphs within the thermodynamic amorphous synthesizability limit and reaffirm the global stability of the rutile structure. We find 75 synthesizable IrO3 polymorphs and report a previously unknown FeF3-type structure as the most stable, termed α-IrO3. To test the algorithms performance, we compare to a random search of the candidate space and report at least a twofold increase in the rate of discovery. Additionally, the AL approach can acquire the most stable polymorphs of IrO2 and IrO3 with less than 30 density functional theory optimizations. Analysis of the structural properties of the discovered polymorphs reveals that octahedral local coordination environments are preferred for nearly all low energy structures. Subsequent Pourbaix Ir-H2O analysis shows that α-IrO3 is the globally stable solid phase under acidic OER conditions and supersedes the stability of rutile IrO2. Calculation of theoretical OER surface activities reveal ideal weaker binding of the OER intermediates on α-IrO3 than on any other considered iridium-oxide. We emphasize that the proposed AL algorithm can be easily generalized to search for any binary metal-oxide structure with a defined stoichiometry.

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Section: Electrochemical Oer Applicationsupporting

confidence: 85%

“…The exact improvement in the theoretical overpotential is slightly dependent on the DFT level of theory and the inclusion of spin polarization, and has been discussed recently. 64,65…”

Section: Electrochemical Oer Applicationmentioning

confidence: 99%

Active Learning Accelerated Discovery of Stable Iridium-oxide Polymorphs for the Oxygen Evolution Reaction

Flores

Paolucci²,

Winther³

et al. 2020

Preprint

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“…Clearly, Li doping benefits the electrocatalytic activity. We also normalized the current densities to the C dl values ( Figure S6) measured in a non-faradaic region of CV to estimate the intrinsic catalytic activity, [24,43,44] as the values of C dl are proportional to the electrochemical surface areas of the samples. [22] The intrinsic activity of Li-doped samples decreased upon Li addition, especially at high Li doping levels.…”

Section: Resultsmentioning

confidence: 99%

On the Stability of Co₃O₄ Oxygen Evolution Electrocatalysts in Acid

et al. 2020

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Oxygen evolution reaction (OER) electrocatalysts suitable to work in acid are typically restricted to platinum group noble metal oxides because of their high activity and, especially, stability. Co3O4 is currently explored as an alternative OER catalyst. Herein we prepared Co3O4 films on fluorine‐doped Sn oxide (FTO) glass and Ti foil via thermal decomposition of nitrate salts and evaluated their activity and stability in 0.05 M H2SO4. Crystalline Co3O4 films deposited on FTO were stable during chronopotentiometry at 10 mA cm−2 for over 16 hours. The dissolution rate was 61 ngCo cm−2 min−1. The choice of a stable support such as FTO is essential to ensure the stability of the catalyst‐substrate interface and to prevent substrate passivation under OER conditions. Doping Co3O4 with Li resulted in a higher OER activity under acidic conditions to be attributed to the larger electrochemical surface area, although the stability was impeded compared to undoped Co3O4.

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“…However, because of the natural rarity and high price of iridium, it is crucial to make the most of this element [9a] . Numerous studies with different synthetic methods have attempted to increase the activity and stability of iridium‐based OECs [9h,l, 10] …”

Section: Introductionmentioning

confidence: 99%

A Simple Method for Synthesizing Highly Active Amorphous Iridium Oxide for Oxygen Evolution under Acidic Conditions

Salimi

Najafpour

2020

Chemistry A European J

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Water splitting for hydrogen production has been recognized as a promising approach to store sustainable energy. The performance of this method is limited by the oxygen‐evolution reaction. Herein, an approach for synthesizing a highly active oxygen‐evolving catalyst by a one‐step, low‐cost, environmentally friendly, and easy‐to‐perform method is presented, which works by using iridium metal as the anode at a relatively high potential. The obtained IrOx/Ir interface showed an overpotential of 250 mV at 10 mA cm−2 in 0.1 m HClO4 and remained stable under electrochemical conditions. The IrOx that was mechanically separated from the surface of IrOx/Ir metal after operation showed a threefold increase in activity compared to the current benchmark IrO2 catalyst. Various characterization analyses were used to identify the structure and morphology of the catalyst, which suggested nanosized, porous, and amorphous IrOx on the surface of metallic Ir. This synthetic approach can inspire a variety of opportunities to design and synthesize efficient metal oxide‐based electrocatalysts for sustainable energy conversion and utilization.

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Systematic Investigation of Iridium-Based Bimetallic Thin Film Catalysts for the Oxygen Evolution Reaction in Acidic Media

Abstract: Thomas F (2019)Systematic Investigation of Iridium-Based Bimetallic Thin Film Catalysts for the Oxygen Evolution Reaction in Acidic Media. ACS Applied Materials and Interfaces, 11 (37). pp. 34059-34066.

Cited by 63 publications

References 62 publications

Active Learning Accelerated Discovery of Stable Iridium-oxide Polymorphs for the Oxygen Evolution Reaction

Active Learning Accelerated Discovery of Stable Iridium-oxide Polymorphs for the Oxygen Evolution Reaction

On the Stability of Co₃O₄ Oxygen Evolution Electrocatalysts in Acid

A Simple Method for Synthesizing Highly Active Amorphous Iridium Oxide for Oxygen Evolution under Acidic Conditions

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Systematic Investigation of Iridium-Based Bimetallic Thin Film Catalysts for the Oxygen Evolution Reaction in Acidic Media

Abstract: Thomas F (2019)Systematic Investigation of Iridium-Based Bimetallic Thin Film Catalysts for the Oxygen Evolution Reaction in Acidic Media. ACS Applied Materials and Interfaces, 11 (37). pp. 34059-34066.

Cited by 63 publications

References 62 publications

Active Learning Accelerated Discovery of Stable Iridium-oxide Polymorphs for the Oxygen Evolution Reaction

Active Learning Accelerated Discovery of Stable Iridium-oxide Polymorphs for the Oxygen Evolution Reaction

On the Stability of Co3O4 Oxygen Evolution Electrocatalysts in Acid

A Simple Method for Synthesizing Highly Active Amorphous Iridium Oxide for Oxygen Evolution under Acidic Conditions

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On the Stability of Co₃O₄ Oxygen Evolution Electrocatalysts in Acid