Ruthenium–platinum core–shell nanocatalysts with substantially enhanced activity and durability towards methanol oxidation

Xie, Jin; Zhang, Qinghua; Gu, Lin; Xu, Sheng; Wang, Peng; Liu, Jianguo; Ding, Yi; Yu, Yao; Nan, Ce‐Wen; Zhao, Ming; You, Yong; Zou, Zhigang

doi:10.1016/j.nanoen.2016.01.013

Cited by 122 publications

(52 citation statements)

References 36 publications

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“…Organic compounds such as alcohols, polyalcohols (polyols), and phenols are attractive for the synthesis of colloidal metal nanocrystals as they can play multiple roles in a reaction, acting as a solvent, and/or stabilizer, in addition to a reductant . Among various alcohols, methanol and ethanol are the most commonly used because of their abundance and relatively lower prices than other alcohols such as n‐propanol, n‐butanol, and 1‐hexanol . In general, primary alcohols always work as reductants due to their superior reactivity relative to secondary and tertiary alcohols.…”

Section: Case Studiesmentioning

confidence: 99%

Synthesis of Colloidal Metal Nanocrystals: A Comprehensive Review on the Reductants

Rodrigues

Zhao

Yang

et al. 2018

Chemistry A European J

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There is a growing interest in controlling the synthesis of colloidal metal nanocrystals and thus tailoring their properties toward various applications. In this context, choosing an appropriate combination of reagents (e.g., salt precursor, reductant, capping agent, and stabilizer) plays a pivotal role in enabling the synthesis of metal nanocrystals with diversified sizes, shapes, and structures. Here we present a comprehensive review that highlights one of the key reagents for the synthesis of metal nanocrystals via chemical reduction: the reductants. We start with a brief introduction to the compounds commonly employed as reductants in the colloidal synthesis of metal nanocrystals by showing their oxidation half-reactions and the corresponding oxidation potentials. Then we offer specific examples pertaining to the controlled synthesis of metal nanocrystals, followed by some fundamental aspects covering the general mechanisms of metal ion reduction based on the Marcus Theory. Afterwards, we present a case-by-case discussion on a wide variety of reductants, including their major properties, reduction mechanisms, and additional effects on the final products. We illustrate these aspects by selecting key examples from the literature and paying close attention to the underlying mechanism in each case. At the end, we conclude by summarizing the highlights of the review and providing some perspectives on future directions.

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Section: Case Studiesmentioning

confidence: 99%

Synthesis of Colloidal Metal Nanocrystals: A Comprehensive Review on the Reductants

Rodrigues

Zhao

Yang

et al. 2018

Chemistry A European J

Self Cite

154

158

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“…However, the lack of active and durable anode catalysts has greatly limited the large-scale commercialization of direct fuel cells. So far, platinum (Pt) has been considered as one of the best catalysts and exclusively utilized in fuel cells23456, but they suffer from high cost and poor carbon monoxide (CO) tolerance8910. Alloying Pt with less expensive oxophilic metals ( M ) such as gold (Au), silver (Ag) and especially nonprecious 3d transition metals11121314 is an effective route to improve CO tolerance and catalytic activity of catalysts, owing to the synergistic and electronic structure alteration mechanism15161718192021222324.…”

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confidence: 99%

Improved ethanol electrooxidation performance by shortening Pd–Ni active site distance in Pd–Ni–P nanocatalysts

et al. 2017

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Incorporating oxophilic metals into noble metal-based catalysts represents an emerging strategy to improve the catalytic performance of electrocatalysts in fuel cells. However, effects of the distance between the noble metal and oxophilic metal active sites on the catalytic performance have rarely been investigated. Herein, we report on ultrasmall (∼5 nm) Pd–Ni–P ternary nanoparticles for ethanol electrooxidation. The activity is improved up to 4.95 A per mgPd, which is 6.88 times higher than commercial Pd/C (0.72 A per mgPd), by shortening the distance between Pd and Ni active sites, achieved through shape transformation from Pd/Ni–P heterodimers into Pd–Ni–P nanoparticles and tuning the Ni/Pd atomic ratio to 1:1. Density functional theory calculations reveal that the improved activity and stability stems from the promoted production of free OH radicals (on Ni active sites) which facilitate the oxidative removal of carbonaceous poison and combination with CH3CO radicals on adjacent Pd active sites.

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“…The {100} facets have been demonstrated to be more active than {111} facets toward alcohol oxidation, which could bind more strongly to alcohol molecules and thus facilitating the CC bond scission . With regard to the durability, the presence of Ru atoms in the nanocages could greatly mitigate CO poisoning of the catalysts by reducing the adsorption energy of CO on the metal surface, which is advantageous to the removal of CO . In particular, Ru atoms in an fcc packing have been reported to exhibit superior performance than their hcp counterpart toward CO oxidation, thus facilitating the removal of CO via oxidation .…”

Section: Resultsmentioning

confidence: 99%

Pd‐Ru Alloy Nanocages with a Face‐Centered Cubic Structure and Their Enhanced Activity toward the Oxidation of Ethylene Glycol and Glycerol

et al. 2020

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drawbacks, including the low boiling point and high toxicity of methanol, together with severe catalyst poisoning during long-term operation. [3,4] To address these issues, one can switch to alcohols with high molecular weights, such as ethylene glycol (EG) and glycerol that feature high boiling points and low toxicity. [5] With regard to the catalyst, an effective strategy is to incorporate Ru into the conventional Pd catalysts for the formation of a Pd-Ru alloy. The alloy-based catalysts are capable of not only enhancing the activity by modulating the electronic structure but also significantly improving the durability owing to the increased resistance to CO poisoning. [6][7][8] Additionally, compared with other precious metals such as Pt and Rh, Ru has a relatively high abundance in the Earth's crust and its current price is about three times lower than those of Pt and Rh, making it promising for the large-scale use in commercial applications. [9] However, Pd and Ru take completely different crystal structures in the bulk, face-centered cubic (fcc) for Pd versus hexagonal close-packed (hcp) for Ru, and their reduction potentials also show significant difference (Pd 2+ /Pd: 0.95 V vs the standard hydrogen electrode (SHE); Ru 3+ /Ru: 0.39 V vs SHE), making it challenging to synthesize Pd-Ru alloy catalysts with controllable compositions and structures. Thus far, the Pd-Ru catalysts reported in literature were mainly based on irregular nanoparticles, and nanoflowers or nanobranches featuring a low content of Ru. [10][11][12][13][14][15][16][17][18] As an alternative to the conventional catalysts based upon solid nanoparticles, nanocages have recently emerged as an intriguing class of catalysts for various reactions. [19][20][21][22][23][24][25] The characteristic hollow structure, ultrathin and porous walls of nanocages are advantageous in maximizing the atom utilization efficiency while the well-controlled surface structures could be leveraged to optimize the active sites. [26,27] One effective route to the synthesis of nanocages is based upon galvanic replacement, which involves the spontaneous reduction of metal ions at the expense of oxidation of a sacrificial template. [28] Moreover, galvanic replacement can be completed within a short period, making it attractive for practical applications. [29][30][31] Regarding the synthesis of Pd-Ru nanocages, despite the well-established protocols for the production of Pd nanocrystals with diverse This article reports a facile method for the synthesis of Pd-Ru nanocages by activating the galvanic replacement reaction between Pd nanocrystals and a Ru(III) precursor with Iions. The as-synthesized nanocages feature a hollow interior, ultrathin wall of ≈2.5 nm in thickness, and a cubic shape. Our quantitative study suggests that the reduction rate of the Ru(III) precursor can be substantially accelerated upon the introduction of Iions and then retarded as the ratio of I -/Ru 3+ is increased. The Pd-Ru nanocages take an alloy structure, with the Ru atoms in the nano cages cr...

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Ruthenium–platinum core–shell nanocatalysts with substantially enhanced activity and durability towards methanol oxidation

Cited by 122 publications

References 36 publications

Synthesis of Colloidal Metal Nanocrystals: A Comprehensive Review on the Reductants

Synthesis of Colloidal Metal Nanocrystals: A Comprehensive Review on the Reductants

Improved ethanol electrooxidation performance by shortening Pd–Ni active site distance in Pd–Ni–P nanocatalysts

Pd‐Ru Alloy Nanocages with a Face‐Centered Cubic Structure and Their Enhanced Activity toward the Oxidation of Ethylene Glycol and Glycerol

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