Factors Influencing the Growth of Pt Nanowires via Chemical Self‐Assembly and their Fuel Cell Performance

Meng, Hui; Zhan, Yunfeng; Zeng, Dongrong; Zhang, Xiaoxue; Zhang, Guoqing; Jaouen, Frédéric

doi:10.1002/smll.201402904

Cited by 31 publications

(21 citation statements)

References 40 publications

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“…Based on the similarities of these agglomerates with previous investigations of Pt NWs grown using formic acid, it seems that the size and shape of the Pt NW agglomerates depends primarily on the underlying seed formed on the support [21,26], and the nanowire growth rate [27]. Control of the growth temperature [19], the separate introduction of seed particles [26], and a variety of other factors such as precursor selection [28] can give better control over this agglomeration. However, the optimisation procedure of the growing process in large quantities is beyond the research topic in this work, considering the principle investigation here is the annealing behaviour.…”

Section: Resultsmentioning

confidence: 95%

Annealing Behaviour of Pt and PtNi Nanowires for Proton Exchange Membrane Fuel Cells

Mardle

2018

Materials

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PtNi alloy and hybrid structures have shown impressive catalytic activities toward the cathodic oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). However, such promise does not often translate into improved electrode performances in PEMFC devices. In this contribution, a Ni impregnation and subsequent annealing method, translatable to vertically aligned nanowire gas diffusion electrodes (GDEs), is shown in thin-film rotating disk electrode measurements (TFRDE) to enhance the ORR mass activity of Pt nanowires (NWs) supported on carbon (Pt NWs/C) by around 1.78 times. Physical characterisation results indicate that this improvement can be attributed to a combination of Ni alloying of the nanowires with retention of the morphology, while demonstrating that Ni can also help improve the thermal stability of Pt NWs. These catalysts are then tested in single PEMFCs. Lower power performances are achieved for PtNi NWs/C than Pt NWs/C. A further investigation confirms the different surface behaviour between Pt NWs and PtNi NWs when in contact with electrolyte ionomer in the electrodes in PEMFC operation. Indications are that this interaction exacerbates reactant mass transport limitations not seen with TFRDE measurements.

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Section: Resultsmentioning

confidence: 95%

Annealing Behaviour of Pt and PtNi Nanowires for Proton Exchange Membrane Fuel Cells

Mardle

2018

Materials

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“…Electrochemically active specific surface areas (ECSA) were analyzed by the oxidation of a CO monolayer, assuming 420 µC cm −2 . Standardization of the real Pt mass by inductively coupled plasma atomic emission spectrometry (ICP‐AES), 3D Pt‐g‐C 3 N 4 ‐rGO exhibits an ECSA value of 80.3 m 2 g −1 , which is far higher than that those of Pt‐g‐C 3 N 4 ‐rGO‐NS (72.2 m 2 g −1 ), Pt‐rGO (68.7 m 2 g −1 ), Pt‐CNT (61.3 m 2 g −1 ), Pt‐AC (44 m 2 g −1 ), and recent state‐of‐the‐art Pt‐based nanocatalysts including Pt‐Ni 2 P/C (69.34 m 2 g −1 ), Pt‐Pd alloy nanoflowers (18.56 m 2 g −1 ), Pd‐Pt nanosheres/RGO (68.1 m 2 g −1 ), Pt/Ti 0.8 Mo 0.2 N (54.9 m 2 g −1 ), Pt nanowires/Vulcan (76.7 m 2 g −1 ), Pt/ionic liquid/CNT (67.6 m 2 g −1 ), etc. This suggests that 3D Pt‐g‐C 3 N 4 ‐rGO not only possesses plenty of catalytically active sites, but also provides more electrochemically accessible surface, which are conducive to electrocatalytic reactions.…”

Section: Resultsmentioning

confidence: 99%

3D Hierarchically Porous Graphitic Carbon Nitride Modified Graphene‐Pt Hybrid as Efficient Methanol Oxidation Catalysts

Zhang

Wang

et al. 2017

Adv Materials Inter

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reducing the amount of Pt, for example, to construct hybrids electrode materials incorporating Pt-based nanocatalysts into carbon support materials, such as porous carbons, [5] carbon nanotubes (CNT), [6,7] and graphene sheets. [8] To improve the surface of chemically inert carbon materials as well as to introduce microspores, several different strategies have been investigated. A useful strategy is chemical activation by using alkali hydroxides as activating agents for pulling in microspores with narrow distribution and increasing their surface areas. [9] Another efficient strategy is heteroatom doping. Recent studies have demonstrated that it is conductive to modulate the electronic structures and chemical reactivity of carbon materials, resulting in the remarkably enhanced catalytic ability. [10] To date, a variety of heteroatom-doped carbon materials and carbon-based hybrids have been developed, such as nitrogen, phosphorus, or boron-doped carbon black, [11] carbon nanotubes, [12] or graphene, [13] nitrogen and sulfur-codoped graphene, [14] and carbon nitride-graphene hybrids. [15][16][17] It is noteworthy that incorporation of heteroatoms into the frameworks of carbon materials can help to remove the absorbed poisoning intermediates, thus ensuring the high exposure of the active sites and promoting the catalytic reaction. [18,19] In particular, graphitic carbon nitride (g-C 3 N 4 ), as a typical nitrogen-rich carbon materials, has become a hot topic of interest due to its remarkable properties including ideal 2D structure, ultrahigh nitrogen content, excellent chemical and thermal stability, which can be applied in a wide range of areas such as metalfree catalysts for water splitting, [20] CO 2 fixation, [21] organic pollutant degradation, [22] and so on.On the other hand, nanostructured materials with hierarchically multimodal pore-size distributions have become a hot topic of interest in the catalytic community owing to that they combine the micro and mesoporosity with the macroporous networks. [23] Rich mesoporosity brings large specific surface areas and the robust macropores lead to accessible diffusion pathways. 3D graphene-based frameworks, such as hydrogel, [24] aerogels, [25,26] foams, [27] and sponges, [28] are an important class of new-generation template-free hierarchically porous materials. 3D graphene-based materials are probably upgraded by the recognition that their high specific surface area and intimate A 3D hierarchically porous carbon nanocomposite constituting of graphitic carbon nitride (g-C 3 N 4 ) chemically integrated with reduced graphene oxide (rGO) via covalent CN bonds is reported. This porous nanocomposite has high nitrogen content, large surface area, interconnected porous networks, and good electrical conductivity, and is used to load Pt nanoparticles to form 3D Pt-g-C 3 N 4 -rGO catalyst for direct methanol fuel cell anode. The catalyst shows an unusual electrocatalytic ability toward methanol electrooxidation, such as high activity, intriguing poison tolerance, and rel...

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“…However, for applications of the Pt/C catalyst, there are still some critical issues to be solved, including sluggish kinetics of the oxygen reduction reaction (ORR), the poor stability, and the expensive price 3. Therefore, a number of strategies have been proposed for enhancing the electrocatalytic properties and reducing the cost of Pt‐based catalysts, such as improving the carbon support,4 changing the morphologies of Pt nanoparticles,5 and synthesizing Pt–M alloy catalysts 6…”

Section: Introductionmentioning

confidence: 99%

Highly Active and Stable Pt–Pd Alloy Catalysts Synthesized by Room‐Temperature Electron Reduction for Oxygen Reduction Reaction

Wang

et al. 2017

Advanced Science

113

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Carbon‐supported platinum (Pt) and palladium (Pd) alloy catalyst has become a promising alternative electrocatalyst for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. In this work, the synthesis of highly active and stable carbon‐supported Pt–Pd alloy catalysts is reported with a room‐temperature electron reduction method. The alloy nanoparticles thus prepared show a particle size around 2.6 nm and a core–shell structure with Pt as the shell. With this structure, the breaking of O–O bands and desorption of OH are both promoted in electrocatalysis of ORR. In comparison with the commercial Pt/C catalyst prepared by conventional method, the mass activity of the Pt–Pd/C catalyst for ORR is shown to increase by a factor of ≈4. After 10 000‐cycle durability test, the Pt–Pd/C catalyst is shown to retain 96.5% of the mass activity, which is much more stable than that of the commercial Pt/C catalyst.

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Factors Influencing the Growth of Pt Nanowires via Chemical Self‐Assembly and their Fuel Cell Performance

Cited by 31 publications

References 40 publications

Annealing Behaviour of Pt and PtNi Nanowires for Proton Exchange Membrane Fuel Cells

Annealing Behaviour of Pt and PtNi Nanowires for Proton Exchange Membrane Fuel Cells

3D Hierarchically Porous Graphitic Carbon Nitride Modified Graphene‐Pt Hybrid as Efficient Methanol Oxidation Catalysts

Highly Active and Stable Pt–Pd Alloy Catalysts Synthesized by Room‐Temperature Electron Reduction for Oxygen Reduction Reaction

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