Alloying Tungsten Carbide Nanoparticles with Tantalum: Impact on Electrochemical Oxidation Resistance and Hydrogen Evolution Activity

Hunt, Sean T.; Kokumai, Tathiana Midori; Zanchet, Daniela; Román‐Leshkov, Yuriy

doi:10.1021/acs.jpcc.5b02922

Cited by 41 publications

(31 citation statements)

References 54 publications

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“…The facile control in a one‐step route is however difficult in traditional TPRe process. For instance, nonsintered WC and Ta 0.3 W 0.7 C were achieved by introducing the hard template of SiO 2 nanoparticles, in which fussy manipulation was required to remove the template.…”

Section: Constructing Tmc Nanostructuresmentioning

confidence: 99%

Structural Design and Electronic Modulation of Transition‐Metal‐Carbide Electrocatalysts toward Efficient Hydrogen Evolution

et al. 2018

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As the key of hydrogen economy, electrocatalytic hydrogen evolution reactions (HERs) depend on the availability of cost-efficient electrocatalysts. Over the past years, there is a rapid rise in noble-metal-free electrocatalysts. Among them, transition metal carbides (TMCs) are highlighted due to their structural and electronic merits, e.g., high conductivity, metallic band states, tunable surface/bulk architectures, etc. Herein, representative efforts and progress made on TMCs are comprehensively reviewed, focusing on the noble-metal-like electronic configuration and the relevant structural/electronic modulation. Briefly, specific nanostructures and carbon-based hybrids are introduced to increase active-site abundance and to promote mass transportation, and heteroatom doping and heterointerface engineering are encouraged to optimize the chemical configurations of active sites toward intrinsically boosted HER kinetics. Finally, a perspective on the future development of TMC electrocatalysts is offered. The overall aim is to shed some light on the exploration of emerging materials in energy chemistry.

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Section: Constructing Tmc Nanostructuresmentioning

confidence: 99%

Structural Design and Electronic Modulation of Transition‐Metal‐Carbide Electrocatalysts toward Efficient Hydrogen Evolution

et al. 2018

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“…The main advantages of such a design over monometallic catalysts are enhanced SA, a drastic decrease in noble metal loading and significant cost benefits . Critically for these materials, the main challenge lies in the stability of the non‐noble material that supports the noble metal layer . State‐of‐the‐art Pt‐based alloys and intermetallic phases with 3d transition metals (TM) such as Pt 3 Ni, Pt 3 Co or Pt 3 Cu equally develop a core‐shell structure during operation until a closed Pt‐film protects the particle interior from dissolution.…”

Section: Introductionmentioning

confidence: 99%

Stable and Active Oxygen Reduction Catalysts with Reduced Noble Metal Loadings through Potential Triggered Support Passivation

et al. 2020

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The development of stable, cost‐efficient and active materials is one of the main challenges in catalysis. The utilization of platinum in the electroreduction of oxygen is a salient example where the development of new material combinations has led to a drastic increase in specific activity compared to bare platinum. These material classes comprise nanostructured thin films, platinum alloys, shape‐controlled nanostructures and core–shell architectures. Excessive platinum substitution, however, leads to structural and catalytic instabilities. Herein, we introduce a catalyst concept that comprises the use of an atomically thin platinum film deposited on a potential‐triggered passivating support. The model catalyst exhibits an equal specific activity with higher atom utilization compared to bulk platinum. By using potential‐triggered passivation of titanium carbide, irregularities in the Pt film heal out via the formation of insoluble oxide species at the solid/liquid interface. The adaptation of the described catalyst design to the nanoscale and to high‐surface‐area structures highlight the potential for stable, passivating catalyst systems for various electrocatalytic reactions such as the oxygen reduction reaction.

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“…33 Alternatively, Ta itself can be used as an elemental addition; both corrosion resistance and ORR activity were improved by adding Ta to tungsten carbide (WC) in WC-Ta alloy. 34,35 In this work, we experimentally report the positive effect of an aliovalent substitution on the ORR, which we attribute to the increased electrical conductivity and possibly increased active sites. Our experiment consists of a series of substitutions, both alio-and isovalent, of tantalum oxynitride, synthesized using urea as a nitrogen source.…”

mentioning

confidence: 55%

Influence of Aliovalent Substitutions on Oxygen Reduction on Tantalum Oxynitrides

Pasqualeti

Padgett

Kuo

et al. 2017

J. Electrochem. Soc.

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The development of active and stable oxygen reduction reaction (ORR) electrocatalysts using low-cost, abundant elements is of critical importance to the widespread adoption of proton-exchanged membrane fuel cells (PEMFCs). Tantalum-containing compounds, such as tantalum oxynitrides, can catalyze ORR in acid, with the degree of oxidation proposed to play a central role in controlling the ORR activity. Herein, we report the incorporation of aliovalent ions in tantalum oxynitrides (Ta-ON) and their effect on the ORR activity in acid. We synthesize Ta-ON by utilizing urea as the nitrogen source and use aliovalent (Ti 4+ ) and isovalent (Nb 5+ ) substitutions to evaluate the influence of the aliovalent substitution on the ORR activity. We found that an aliovalent Ti 4+ substitution increases the ORR activity by 3x, which we attribute to improved electrical conductivity and increased ORR active sites. In comparison, isovalent Nb 5+ substitution or carbon inclusion as oxycarbonitride did not positively affect the ORR activity. Our finding points to the important role of defects and conductivity in the Ta Active, acid-stable, and cost-effective cathodes for the oxygen reduction reaction (ORR) play an enabling role in the commercialization of proton-exchanged membrane fuel cells (PEMFCs). Platinum nanoparticles supported on high surface-area carbon supports (Pt/C) are currently the most active ORR electrocatalyst; 1 however, there are concerns with the scalability and stability 2 of Pt. 3,4 To identify alternatives, many groups have examined non-Pt ORR electrocatalysts made of inorganic, organic, and hybrid organic-inorganic materials. Examples include Fe-N-C, 5 and polyaniline (PANI)-Fe/Co-C, 6,7 some of which have ORR kinetics almost already comparable to Pt/C. 8,9 However, these electrocatalysts are not yet stable under longterm operations.3 While many efforts have been made to improve the stability 10 and identify the active sites, 11 long-term stability of these carbon-based electrocatalysts remains a challenge.Valve metal compounds such as tantalum-based compounds are among a few classes of non-precious-metal materials that are stable in acid.12 Their exceptional stability has spurred investigations of how they can be used as electrocatalysts. Examples include tantalum oxynitride (TaON) and tantalum nitride (Ta 3 N 5 ), which have also been investigated for solar-driven water splitting. [13][14][15][16] However, most valvemetal oxides are not active toward the ORR. As a result, significant efforts have been devoted to activating these materials for the ORR. Ota et al. have shown that controlling the degree of oxidation can improve the ORR in tantalum oxynitrides.17,18 By surveying TaC x N y , 17Ta-CNO 17,19 and TaO x N y /Ti, 20 they have proposed that an ideal interaction between the oxygen molecule and the surface tantalum must be optimized via this degree of oxidation to improve the ORR activity. 21The same group has also demonstrated correlations between the ORR and oxygen vacancies, which they proposed as the ...

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Alloying Tungsten Carbide Nanoparticles with Tantalum: Impact on Electrochemical Oxidation Resistance and Hydrogen Evolution Activity

Cited by 41 publications

References 54 publications

Structural Design and Electronic Modulation of Transition‐Metal‐Carbide Electrocatalysts toward Efficient Hydrogen Evolution

Structural Design and Electronic Modulation of Transition‐Metal‐Carbide Electrocatalysts toward Efficient Hydrogen Evolution

Stable and Active Oxygen Reduction Catalysts with Reduced Noble Metal Loadings through Potential Triggered Support Passivation

Influence of Aliovalent Substitutions on Oxygen Reduction on Tantalum Oxynitrides

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