Ru@Pt core–shell nanoparticles for methanol fuel cell catalyst: Control and effects of shell composition

Muthuswamy, Navaneethan; Fuente, José Luis Gómez de la; Tran, Dung Trung; Walmsley, John C.; Tsypkin, Mikhail; Raaen, S.; Sunde, Svein; Rønning, Magnus; Chen, De

doi:10.1016/j.ijhydene.2013.02.056

Cited by 70 publications

(50 citation statements)

References 35 publications

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“…48 However, once a complete 2 ML Pt shell was realized, a single CO stripping peak was obtained at a more positive potential than that of the single peak obtained for the r1 ML Pt, as the electronic effect of Ru on the second layer of Pt atoms is buffered by the underlying Pt. 29 The NPs with what was assumed to be the highest degree of Pt-Ru alloying in the shell layer showed the highest MOR activity, suggesting that both the bi-functional and electronic effects of Ru are relevant, but with the bi-functional effect being dominant. 48 In terms of the activity of Ru@Pt NPs towards the MOR, 29,45 Muthuswamy et al reported that the Pt : Ru ratio in Ru@Pt shell NPs increased upon increasing solution pH during the encapsulation of the Ru core with Pt, according to X-ray Photoelectron Spectroscopy (XPS) results.…”

Section: Introductionmentioning

confidence: 93%

“…When 1-2 monolayers of the Pt shell were present, two CO stripping peaks appeared due to the presence of two types of Pt atoms, each having different electronic properties. 48 In terms of the activity of Ru@Pt NPs towards the MOR, 29,45 Muthuswamy et al reported that the Pt : Ru ratio in Ru@Pt shell NPs increased upon increasing solution pH during the encapsulation of the Ru core with Pt, according to X-ray Photoelectron Spectroscopy (XPS) results. 23 On the other hand, the CO oxidation process was shown to be independent of the Ru core size.…”

Section: Introductionmentioning

confidence: 99%

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Clarifying the role of Ru in methanol oxidation at Ru_core@Pt_shellnanoparticles

Sawy

El‐Sayed

Birss

2015

Phys. Chem. Chem. Phys.

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The catalytic activity of Rucore@Ptshell nanoparticles (NPs) towards CO oxidation, a strongly adsorbed intermediate that compromises the performance of direct methanol fuel cells, is known to be significantly better than at Pt alone. However, a systematic study aimed at understanding the beneficial effect of Ru on Pt during the methanol oxidation reaction (MOR) has not been carried out as yet. Here, Rucore@Ptshell NPs, having a controlled Ptshell coverage of zero to two monolayers and two different Rucore sizes (2 and 3 nm), were synthesized using the simple polyol method to determine the precise role and impact of Ru on the MOR in 0.5 M H2SO4 + 1 M methanol at RT and 60 °C. Because the structure of our Rucore@Ptshell NPs is known with such certainty, we were able to show here that the rate of methanol adsorption/dehydrogenation can be accelerated either by compression of the Ptshell (by making the Rucore larger) when it is less than one monolayer in thickness, or by decreasing the electronic effect of the Rucore on the Ptshell (achieved by adding a second Pt layer to the Ptshell). At low overpotentials, decreasing the Ptshell thickness also helps in increasing the rate of the MOR by enhancing the rate of oxidation of adsorbed CO. Finally, it is shown that the bi-functional effect of Ru on the Ptshell plays only a minor role in the catalysis of the MOR, especially at large particles where CO surface diffusion is facilitated.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Clarifying the role of Ru in methanol oxidation at Ru_core@Pt_shellnanoparticles

Sawy

El‐Sayed

Birss

2015

Phys. Chem. Chem. Phys.

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“…It is well acknowledged that PtRu catalysts had better MOR activity than commercial Pt/C due to the formation of bimetallic structure. 36 During the reaction, a monolayer Pt-O or Pt-CO on the surface would repeat the generation or consumption process during the voltage scanning. Therefore the surface of catalysts could maintain clean in the test environment even if the surface of the catalyst was oxidized at the beginning.…”

Section: Resultsmentioning

confidence: 99%

Facile synthesis of Pd@Pt octahedra supported on carbon for electrocatalytic applications

Zhang

Dong

et al. 2017

AIChE Journal

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Due to the scarcity of Pt, it is highly desirable to construct core‐shell structures with ultrathin Pt shells while maintaining their high electrocatalytic activities. However, it is necessary to preferentially synthesize a core with a specific structure before further formation of core‐shell catalysts with specific morphologies. This prerequisite greatly increases the complexity of the synthesis process. This article describes a synthetic method of core‐shell Pd@Pt octahedra catalysts from Pd nanocubes, truncated nanocubes or truncated octahedra. The formation of octahedral core‐shell structures involves two key factors: (1) the oxidative etching process of Pd atoms at the corner sites; (2) the different reduction rates between Pt and Pd precursors. This mechanism can be extended to synthesize carbon‐supported sub‐8 nm Pd@Pt octahedra from commercial Pd/C catalysts. The derived carbon‐supported Pd@Pt octahedra catalysts performed comparable activity and durability for methanol oxidation reaction with state‐of‐art PtRu/C catalysts. This synthetic method provides an innovative path for large‐scale production of well‐controlled catalysts. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2528–2534, 2017

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“…Recent experimental and DFT results have demonstrated that Pt monolayers coated on Ru possess substantially enhanced catalytic activities for CO oxidation through a novel pathway of weakly bonded Pt-(OH) ads on the Pt monolayer/Ru nanomaterial originating from compressive strains resulting from the apparent lattice mismatch (2.55%) between Pt and Ru [35,111,132,177,[415][416][417]. And because of these reported performance enhancements, many types of Ru@Pt core-shell-structured electrocatalysts have been synthesized by using different procedures by researchers and have been reported to produce enhanced catalytic activities for MORs [93,95,113,176,305,328,[418][419][420][421][422][423][424]. For example, a Ru@ Pt core-shell catalyst possessing a 3 nm core and a 3~4 atom layer Pt shell was prepared by using the PED (Fig.…”

Section: Ru As Corementioning

confidence: 99%

Core–Shell-Structured Low-Platinum Electrocatalysts for Fuel Cell Applications

Wang

Luo

et al. 2018

Electrochem. Energ. Rev.

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Pt-based catalysts are the most efficient catalysts for low-temperature fuel cells. However, commercialization is impeded by prohibitively high costs and scarcity. One of the most effective strategies to reduce Pt loading is to deposit a monolayer or a few layers of Pt over other metal cores to form core-shell-structured electrocatalysts. In core-shell-structured electrocatalysts, the compositions of the core can be divided into five classes: single-precious metallic cores represented by Pd, Ru, and Au; singlenon-precious metallic cores represented by Cu, Ni, Co, and Fe; alloy cores containing 3d, 4d or 5d metals; and carbide and nitride cores. Of these, researchers have found that carbide and nitride cores can yield tremendous advantages over alloy cores in terms of cost and promotional activities of Pt shells. In addition, desirable shells with reasonable thicknesses and compositions have been recognized to play a dominant role in electrocatalytic performances. And recently, researchers have also found that the catalytic activity of core-shell-structured catalysts is dependent on the binding energy of the adsorbents, which is determined by the d-band center of Pt. The shifting of this d-band center in turn is mainly affected by strain and electronic effects, which can be adjusted by adjusting core compositions and shell thicknesses of catalysts. In the development of these core-shell structures, optimal synthesis methods are of primary concern because they directly determine the practical application potential of the resulting electrocatalysts. And in this article, the principles behind core-shell-structured low-Pt electrocatalysts and the developmental progresses of various synthesis methods along with the traits of each type of core and its effects on Pt shell catalytic activities are discussed. In addition, perspectives on this type of catalyst are discussed and future research directions are proposed.

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Ru@Pt core–shell nanoparticles for methanol fuel cell catalyst: Control and effects of shell composition

Cited by 70 publications

References 35 publications

Clarifying the role of Ru in methanol oxidation at Ru_core@Pt_shellnanoparticles

Clarifying the role of Ru in methanol oxidation at Ru_core@Pt_shellnanoparticles

Facile synthesis of Pd@Pt octahedra supported on carbon for electrocatalytic applications

Core–Shell-Structured Low-Platinum Electrocatalysts for Fuel Cell Applications

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Ru@Pt core–shell nanoparticles for methanol fuel cell catalyst: Control and effects of shell composition

Cited by 70 publications

References 35 publications

Clarifying the role of Ru in methanol oxidation at Rucore@Ptshellnanoparticles

Clarifying the role of Ru in methanol oxidation at Rucore@Ptshellnanoparticles

Facile synthesis of Pd@Pt octahedra supported on carbon for electrocatalytic applications

Core–Shell-Structured Low-Platinum Electrocatalysts for Fuel Cell Applications

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Product

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Clarifying the role of Ru in methanol oxidation at Ru_core@Pt_shellnanoparticles

Clarifying the role of Ru in methanol oxidation at Ru_core@Pt_shellnanoparticles