Synthesis of Ultrathin Palladium and Platinum Nanowires and a Study of Their Magnetic Properties

Teng, Xiaowei; Han, Wei‐Qiang; Ku, Wei; Hücker, M.

doi:10.1002/ange.200704707

Cited by 48 publications

(44 citation statements)

References 31 publications

(16 reference statements)

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“…Unlike previous reports involving utilization of Pt electrodes 8,[19][20][21][22] , the selection of single-layered 2D Ni(OH) 2 (SL-Ni(OH) 2 ) nanosheets as the substrates is based on cost considerations 28,29 , as SL-Ni(OH) 2 sheets might be cheaply acquired via exfoliation of lamellar a-Ni(OH) 2 (refs 30-33). Furthermore, compared with commonly used zero-dimensional (0D) Pt nanoparticles (NPs), 1D ultrathin Pt NWs of high aspect ratios, few lattice boundaries and smooth crystal planes offer the opportunity for improvement of the catalytic activity [34][35][36][37][38][39][40][41][42][43][44] . Meanwhile, a large contact area between Pt NWs and the Ni(OH) 2 substrates can effectively alleviate possible migration and aggregation of Pt NWs and thus benefit enhancement of the catalytic stability 40 .…”

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confidence: 99%

Ultrathin platinum nanowires grown on single-layered nickel hydroxide with high hydrogen evolution activity

et al. 2015

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Design and synthesis of effective electrocatalysts for hydrogen evolution reaction in alkaline environments is critical to reduce energy losses in alkaline water electrolysis. Here we report a hybrid nanomaterial comprising of one-dimensional ultrathin platinum nanowires grown on two-dimensional single-layered nickel hydroxide. Judicious surface chemistry to generate the fully exfoliated nickel hydroxide single layers is explored to be the key for controllable growth of ultrathin platinum nanowires with diameters of about 1.8 nm. Impressively, this hybrid nanomaterial exhibits superior electrocatalytic activity for hydrogen evolution reaction in alkaline solution, which outperforms currently reported catalysts, and the obviously improved catalytic stability. We believe that this work may lead towards the development of singlelayered metal hydroxide-based hybrid materials for applications in catalysis and energy conversion.

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confidence: 99%

Ultrathin platinum nanowires grown on single-layered nickel hydroxide with high hydrogen evolution activity

et al. 2015

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“…Symbols show the measured magnetic correlation length, and the curve shows the temperature dependence expected from the Curie-Weiss law, which extrapolates to the Curie temperature of about 90 K. However, the correlation length significantly deviates from the Curie-Weiss law at temperatures below 110 K, and starts to decrease at T < 25 K, suggesting that magnetism in Pt is increasingly suppressed at low temperatures. Indeed, bulk Pt remains an exchange-enhanced paramagnet even at cryogenic temperatures, while ferromagnetism was reported only in ultrathin films and nanoparticles [49][50][51].…”

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Evidence for Dyakonov-Perel-like Spin Relaxation in Pt

et al. 2018

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We utilize nanoscale spin valves with Pt spacer layers to characterize spin scattering in Pt. Analysis of the spin lifetime determined from our measurements indicates that the extrinsic Elliot-Yafet spin scattering is dominant at room temperature, while the intrinsic Dyakonov-Perel mechanism dominates at cryogenic temperatures. The significance of the latter is supported by the suppression of spin relaxation in Pt layers interfaced with a ferromagnet, likely caused by the competition between the effective exchange and spin-orbit fields.The interplay between electron's motion and its spin due to the spin-orbit interaction (SOI) opens unprecedented opportunities for the control of both spin and orbital degrees of freedom [1][2][3][4][5]. For instance, the spin Hall effect (SHE) results in generation of pure spin current flowing transverse to charge current [6], enabling electronic control of static and dynamic states of magnetization in metallic and insulating nanomagnets [7][8][9]. Extensive recent studies of materials that exhibit large SOI, including Pt, Ta, W, topological insulators, and alloys such as CuBi, have focused on identifying the intrinsic and extrinsic mechanisms controlling SOI, and characterizing the relevant parameters including the spin-orbit scattering rates, the spin Hall angle, and the effective spin-orbit field [10][11][12][13][14][15][16][17]. Another relevant parameter is the spin diffusion length λ, defined as the length scale over which the spin polarization relaxes away from the external source, which is determined mostly by the spin scattering due to SOI. It is also the length scale for spin current generation via the SHE, and is thus directly related to material's performance in spin-Hall applications.Pt is one of the most extensively studied spin-orbit materials, thanks to the large SOI effects [10,18,19], relatively low resistivity that minimizes Joule heating and current shunting in heterostructures, and low reactivity. A variety of approaches have been utilized to determine the parameters relevant to SOI in Pt such as the spin Hall angle and λ [10,14,18,[20][21][22]. Nevertheless, the values and the mechanisms controlling these parameters are still debated. In particular, the reported values of the spin Hall angle in Pt range from 0.004 to over 0.1 [10,14,23], and those of λ range from less than 1 nm to over 10 nm [10,14,18,[20][21][22][24][25][26]. Such a large spread of the reported characteristics makes it challenging to establish the dominant contributions to spin-orbit effects and the mechanisms controlling them.One of the main difficulties in analyzing SOI is posed by the interplay between the interfacial and bulk effects. For instance, measurements of spin current generated by SHE are inevitably affected by the spin relaxation at the Pt interfaces, and by its generation via the interfacial Rashba effect [27]. Indeed, the apparent spin Hall angle has been shown to depend on the transparency of the interfaces [23]. Measurements of λ based on the spin absorption efficiency [21...

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“…The NCs obtained by this method have been applied in physical and chemical fields. However, when needed, it is essential to diminish or eliminate the role of oxidative etching in the reaction system [388,389]. In short, if controlled appropriately, oxidative etching provides accessibility and possibility for synthesizing NCs and refining their function for application.…”

Section: Structure Controlmentioning

confidence: 99%

Understanding of the major reactions in solution synthesis of functional nanomaterials

Wang

2016

Sci. China Mater.

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This review covers the major reactions involved in the solution synthesis of nanomaterials. It was designed to classify the traditional strategies such as precipitation, reduction, seed growth, etching, and so on into two basic processes which are termed as bottom-up and top-down routines. The discussion is focused on the basic mechanism and principles during the nucleation and growth of nanocrystals, especially in the solution system. This review also presents a prediction for how to utilize these intrinsic processes to artificially construct the desired specific and functional nanostructures. We try to describe the most directive and effective way to control the structures of nanocrystals for researchers who can master the major reaction mechanism and grasp the basic technologies in synthetic nanoscience.

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Synthesis of Ultrathin Palladium and Platinum Nanowires and a Study of Their Magnetic Properties

Cited by 48 publications

References 31 publications

Ultrathin platinum nanowires grown on single-layered nickel hydroxide with high hydrogen evolution activity

Ultrathin platinum nanowires grown on single-layered nickel hydroxide with high hydrogen evolution activity

Evidence for Dyakonov-Perel-like Spin Relaxation in Pt

Understanding of the major reactions in solution synthesis of functional nanomaterials

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