Enhancing Iridium Nanoparticles’ Oxygen Evolution Reaction Activity and Stability by Adjusting the Coverage of Titanium Oxynitride Flakes on Reduced Graphene Oxide Nanoribbons’ Support

Moriau, Léonard; Podboršek, Gorazd Koderman; Šurca, Angelja Kjara; Parpari, Sorour Semsari; Šala, Martin; Petek, Urša; Bele, Marjan; Jovanovič, Primož; Genorio, Boštjan; Hodnik, Nejc

doi:10.1002/admi.202100900

Cited by 11 publications

(17 citation statements)

References 96 publications

(171 reference statements)

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“…32 A Tafel slope of ∼60 mV dec −1 was determined (Figure 1c). This value is comparable to the literature values of TiON-supported Ir analogues 29,30,32 as well as with both the bulk, rutile IrO 2 , and the electrochemically grown oxide, 22,41−43 indicating that no significant mechanistic difference in OER with respect to other Ir-based catalysts exists. Subsequently, two-sequence long-term electrochemical protocols (EC-P and EC-CV; described in detail in the Experimental Section) were performed and complemented with detailed statistical STEM analysis of preselected locations (i.e., identical location, IL-STEM mode).…”

Section: ■ Resultssupporting

confidence: 86%

“…Preliminary studies have demonstrated several promising aspects of TiON-based supports for OER. Briefly, sufficiently high dispersion of iridium nanoparticles accompanied with nanotubular or nanoribbon-like support morphology and strong metal–support interactions (SMSI) , has been documented. Therefore, further insights on resolving and understanding TiON as the OER support are justifiably needed.…”

Section: Introductionmentioning

confidence: 99%

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Iridium Stabilizes Ceramic Titanium Oxynitride Support for Oxygen Evolution Reaction

et al. 2022

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Decreasing iridium loading in the electrocatalyst presents a crucial challenge in the implementation of proton exchange membrane (PEM) electrolyzers. In this respect, fine dispersion of Ir on electrically conductive ceramic supports is a promising strategy. However, the supporting material needs to meet the demanding requirements such as structural stability and electrical conductivity under harsh oxygen evolution reaction (OER) conditions. Herein, nanotubular titanium oxynitride (TiON) is studied as a support for iridium nanoparticles. Atomically resolved structural and compositional transformations of TiON during OER were followed using a task-specific advanced characterization platform. This combined the electrochemical treatment under floating electrode configuration and identical location transmission electron microscopy (IL-TEM) analysis of an in-house-prepared Ir-TiON TEM grid. Exhaustive characterization, supported by density functional theory (DFT) calculations, demonstrates and confirms that both the Ir nanoparticles and single atoms induce a stabilizing effect on the ceramic support via marked suppression of the oxidation tendency of TiON under OER conditions.

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Section: ■ Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Iridium Stabilizes Ceramic Titanium Oxynitride Support for Oxygen Evolution Reaction

et al. 2022

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“…1300 m 2 /g - BET) was also beneficial for the preparation and fine dispersion of the high-surface-area TiON x . The possible effect of carbon on the electrocatalytic performance was not part of this study; however, it was recently addressed in a study published by Moriau et al The authors have shown that the coverage of reduced graphene oxide nanoribbons with TiON x has a beneficial effect on the electrocatalytic properties of Ir nanoparticles compared to Ir nanoparticles supported only on reduced graphene oxide nanoribbons.…”

Section: Resultsmentioning

confidence: 99%

Sacrificial Cu Layer Mediated the Formation of an Active and Stable Supported Iridium Oxygen Evolution Reaction Electrocatalyst

et al. 2021

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The production of hydrogen via a proton-exchange membrane water electrolyzer (PEM-WE) is directly dependent on the rational design of electrocatalysts for the anodic oxygen evolution reaction (OER), which is the bottleneck of the process. Here, we present a smart design strategy for enhancing Ir utilization and stabilization. We showcase it on a catalyst, where Ir nanoparticles are efficiently anchored on a conductive support titanium oxynitride (TiON x ) dispersed over carbon-based Ketjen Black and covered by a thin layer of copper (Ir/CuTiON x /C), which gets removed in the preconditioning step. Electrochemical OER activity, stability, and structural changes were compared to the Ir-based catalyst, where Ir nanoparticles without Cu are deposited on the same support (Ir/TiON x /C). To study the effect of the sacrificial less-noble metal layer on the catalytic performance of the synthesized material, characterization methods, namely X-ray powder diffraction, X-ray photoemission spectroscopy, and identical location transmission electron microscopy were employed and complemented with scanning flow cell coupled to an inductively coupled plasma mass spectrometer, which allowed studying the online dissolution during the catalytic reaction. Utilization of these advanced methods revealed that the sacrificial Cu layer positively affects both Ir OER mass activity and its durability, which was assessed via S-number, a recently reported stability metric. Improved activity of Cu analogue was ascribed to the higher surface area of smaller Ir nanoparticles, which are better stabilized through a strong metal–support interaction (SMSI) effect.

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“…Several support materials have been investigated, including various oxides, such as pure SnO 2 ; Sb- (ATO), ,,,, In- (ITO), , F- (FTO), Ta- (TaTO), and Nb-doped (NTO) , tin oxides (TO = tin oxide); NbO 2 ; WO 3 ; WO x ; MoO 3 ; TiO 2, , nonstoichiometric TiO x ; − W-, Ta-, or Nb-doped , titanium oxides; titanium nitrides and oxynitrides; , carbides, such as TaC, , TiC, NbC, WC, SiC–C, B 4 C, and others. Most of the proposed materials possess high electronic conductivity and stability.…”

Section: Supported Ir-based Catalysts For Oer: Problem Statementmentioning

confidence: 99%

Supported Ir-Based Oxygen Evolution Catalysts for Polymer Electrolyte Membrane Water Electrolysis: A Minireview

2022

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Renewable energy sources are considered to play a key role in the future energy mix, with hydrogen being an important energy carrier as a long-term energy storage option. Polymer electrolyte membrane (PEM) water electrolysis (WE) allows the relatively quick and convenient production of pure hydrogen from only water and electricity; thus it is considered as one of the most practical ways to consume renewable energy for green hydrogen production. The efficiency of water splitting largely depends on the intrinsic activity, selectivity, and stability of the oxygen evolution electrocatalysts, currently based on noble metals (e.g., Ir or Ru), for PEM technology. The utilization of various support materials has been proposed for decreasing the noble metal loading, reducing costs of the technology, and enhancing the catalytic activity and durability. This minireview addresses recent advances and research prospects in the area of Ir-based supported oxygen evolution catalysts. Besides addressing the intrinsic activity and durability of the supported catalysts, consideration is given to their applications in PEM WE cells. It concludes with mention of challenges and future perspectives.

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Enhancing Iridium Nanoparticles’ Oxygen Evolution Reaction Activity and Stability by Adjusting the Coverage of Titanium Oxynitride Flakes on Reduced Graphene Oxide Nanoribbons’ Support

Abstract: The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/admi.202100900.

Cited by 11 publications

References 96 publications

Iridium Stabilizes Ceramic Titanium Oxynitride Support for Oxygen Evolution Reaction

Iridium Stabilizes Ceramic Titanium Oxynitride Support for Oxygen Evolution Reaction

Sacrificial Cu Layer Mediated the Formation of an Active and Stable Supported Iridium Oxygen Evolution Reaction Electrocatalyst

Supported Ir-Based Oxygen Evolution Catalysts for Polymer Electrolyte Membrane Water Electrolysis: A Minireview

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