Ultrathin oxide shell coating of metal nanoparticles using ionic liquid/metal sputtering

Torimoto, Tsukasa; Ohta, Yasuhiro; Enokida, Kazuki; Sugioka, Daisuke; Kameyama, Tatsuya; Yamamoto, Takahisa; Shibayama, Tamaki; Yoshii, Kazuki; Tsuda, Tetsuya; Kuwabata, Susumu

doi:10.1039/c4ta06643j

Cited by 37 publications

(34 citation statements)

References 54 publications

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“…The unique features of an IL, such as a negligible vapor pressure, wide electrochemical window, good thermal stability, antistatic properties, have led to many proposed applications thus far. Recently, we reported Pt‐nanoparticle‐supported carbon electrocatalysts easily produced by agitating Pt‐nanoparticle‐monodispersed ILs, which were prepared by magnetron sputtering onto the ILs, with various carbon supports, e.g., carbon nanotubes and carbon black, under heating conditions . The resulting electrocatalysts showed favorable catalytic activities for ORR and high durabilities .…”

Section: Summary Of the Pt‐nanoparticle‐supported Carbon Catalysts Usmentioning

confidence: 99%

Pt‐Nanoparticle‐Supported Carbon Electrocatalysts Functionalized with a Protic Ionic Liquid and Organic Salt

Izumi

Tsuda

et al. 2017

Adv Materials Inter

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this corrosion, including the use of sp 2carbon materials without functional groups, i.e., carbon nanotubes [11] and graphene, [12] and noncarbon materials [13] as nanoparticle supports and the decoration of the Pt nanoparticles on carbon. [14] Although these approaches have been effective in reducing the degradation to varying degrees, unfortunately, further developments are required due to the high costs, complex preparation procedures, and insufficient electrode performances resulting from these approaches. Hence, developing an effective approach to provide high electrocatalytic activity and catalyst stability is a great challenge.An ionic liquid (IL) is a liquid salt consisting of a cation and anion at room temperature and is a subset of a molten salt. The unique features of an IL, such as a negligible vapor pressure, wide electrochemical window, good thermal stability, antistatic properties, have led to many proposed applications thus far. Recently, we reported Pt-nanoparticle-supported carbon electrocatalysts easily produced by agitating Pt-nanoparticle-monodispersed ILs, which were prepared by magnetron sputtering onto the ILs, [15,16] with various carbon supports, e.g., carbon nanotubes and carbon black, under heating conditions. [17][18][19][20][21][22] The resulting electrocatalysts showed favorable catalytic activities for ORR and high durabilities. [23] The latter feature was attributed to the thin IL layer between the Pt nanoparticles and carbon support, which suppressed carbon corrosion. [23] ILs should play key roles in the further improvement of electrocatalysts. Here, we focused on a protic organic salt (POS) and protic ionic liquid (PIL) that are easily synthesized, a cost-effective option and often show desirable physicochemical properties over commonly used ILs. [24][25][26][27] To reveal the effects of the ILs on the catalytic activities of the resulting Pt-nanoparticle-supported carbon materials, diphenylammonium hydrogen sulfate ([DPA][HSO 4 ]) and N,N-diethyl-N-methylammonium hydrogen sulfate ([DEMA] [HSO 4 ]) were exploited in this investigation as a POS and a PIL, respectively. The aim of this study is to disclose approaches to improve the performances of electrocatalysts for PEFCs.[DPA] [HSO 4 ] and [DEMA] [HSO 4 ] were prepared by procedures described in previous articles. [26,27] [DEMA] [HSO 4 ] was used in a sputtering process to produce a Pt-nanoparticlemonodispersed IL.[DPA] [HSO 4 ], which is a solid salt at room temperature, was used as an additive to provide functionality to the Pt-nanoparticle-supported carbon materials. In this article, electrocatalysts prepared with and without [DPA][HSO 4 ] Pt-nanoparticle-supported carbon catalysts for the electrochemical oxygen reduction reaction produced using a Pt-nanoparticle-monodispersed ionic liquid (IL) show better durability than a commercially available catalyst due to the small amount of IL between the Pt nanoparticles and the carbon support. In this study, to add further functionality to the catalysts prepared with the Pt-na...

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Section: Summary Of the Pt‐nanoparticle‐supported Carbon Catalysts Usmentioning

confidence: 99%

Pt‐Nanoparticle‐Supported Carbon Electrocatalysts Functionalized with a Protic Ionic Liquid and Organic Salt

Izumi

Tsuda

et al. 2017

Adv Materials Inter

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“…X-ray photoelectron spectroscopy (XPS) 33 and a transmission electron microscope (TEM) equipped with energy dispersive spectroscopy (EDS) were also used to confirm the oxidization of boron and identify oxide shells 34 on the boron surface. The formation of surface oxide is supposed to decrease the potential energy (explosive energy) of the system and disturb the propagation of combustion 10 .…”

Section: Introductionmentioning

confidence: 99%

Study on the Aging Mechanism of Boron Potassium Nitrate (BKNO3) for Sustainable Efficiency in Pyrotechnic Mechanical Devices

Lee

Kim

Ryu

et al. 2018

Sci Rep

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The aging of propellants in PMDs is considered to be one of the primary factors affecting the performance of PMDs. Thus, studies on the aging mechanism of propellants, which have not yet been addressed extensively, pose a solution to securing the sustainable operation of PMDs. We characterized one of the most commonly used commercial propellants (boron potassium nitrate (BKNO3)) and investigated its aging mechanism rigorously. Based on thermal analyses, we demonstrate that the decomposition of laminac, a polymer binder, is the fastest spontaneous reaction. However, it will not self-initiate at a storage temperature as high as 120 °C. The effect of the humidity level was examined by characterizing BKNO3 samples prepared. The heat of reaction and the reaction rate decreased by 18% and 67% over 16 weeks of aging, respectively. This is attributed to the oxide shells on the surface of boron particles. The formation of oxide shells could be confirmed using X-ray photoelectron spectroscopy and transmission electron microscopy–energy dispersive spectroscopy. In conclusion, surface oxide formation with the aging of BKNO3 will decrease its propulsive efficiency; oxidation reduces the potential energy of the system and the resulting oxide decreases the reaction rate.

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“…One thing to take into consideration though is that it is difficult to support Pt nanoparticles onto these carbon materials without breaking down the sp 2 structure due to their surface inertness. 23 We recently found that various metal nanoparticles, prepared by metal magnetron sputtering onto an ionic liquid (IL), 24,25 can be easily supported by carbon materials by heat treatment without the requirement of any further process, [26][27][28][29][30][31] e.g., glassy carbon (GC), highly oriented pyrolytic carbon (HOPG), and single-walled carbon nanotubes (SWCNTs), and thus concluded that the IL works as a glue to support the Pt nanoparticles onto these materials. 30 Very recently, Su et al proposed a similar idea, namely that a very thin IL layer could be formed on a nanocarbon material via an entrapping effect.…”

Section: Introductionmentioning

confidence: 99%

Highly durable Pt nanoparticle-supported carbon catalysts for the oxygen reduction reaction tailored by using an ionic liquid thin layer

et al. 2016

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Ultrathin oxide shell coating of metal nanoparticles using ionic liquid/metal sputtering

Abstract: The indium sputter deposition into ionic liquids containing noble metal nanoparticles produces core–shell-structured metal@In2O3 with high thermal and electrochemical stability.

Cited by 37 publications

References 54 publications

Pt‐Nanoparticle‐Supported Carbon Electrocatalysts Functionalized with a Protic Ionic Liquid and Organic Salt

Pt‐Nanoparticle‐Supported Carbon Electrocatalysts Functionalized with a Protic Ionic Liquid and Organic Salt

Study on the Aging Mechanism of Boron Potassium Nitrate (BKNO3) for Sustainable Efficiency in Pyrotechnic Mechanical Devices

Highly durable Pt nanoparticle-supported carbon catalysts for the oxygen reduction reaction tailored by using an ionic liquid thin layer

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