Template‐Free Synthesis and Assembly of Single‐Crystalline Tungsten Oxide Nanowires and their Gas‐Sensing Properties

Polleux, Julien; Gurlo, Aleksander; Bârsan, Nicolae; Weimar, Udo; Antonietti, Markus; Niederberger, Markus

doi:10.1002/anie.200502823

Cited by 338 publications

(194 citation statements)

References 49 publications

(42 reference statements)

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“…The reaction of tungsten isopropoxide with benzyl alcohol represents an example in which another oxidation product of benzyl alcohol played the critical role in determining particle shape and assembly behavior. 51 The as-synthesized tungsten oxide consists of nanowire bundles that are held together by intercalated benzaldehyde molecules. The bundles can be split up into individual nanowires with uniform diameters of 1 nm by the addition of formamide to a dispersion of the nanobundles in ethanol (Figure 3c).…”

Section: Remarks On the Role Of The Organicsmentioning

confidence: 99%

Nonaqueous Sol–Gel Routes to Metal Oxide Nanoparticles

2007

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Sol-gel routes to metal oxide nanoparticles in organic solvents under exclusion of water have become a versatile alternative to aqueous methods. In comparison to the complex aqueous chemistry, nonaqueous processes offer the possibility of better understanding and controlling the reaction pathways on a molecular level, enabling the synthesis of nanomaterials with high crystallinity and well-defined and uniform particle morphologies. The organic components strongly influence the composition, size, shape, and surface properties of the inorganic product, underlining the demand to understand the role of the organic species at all stages of these processes for the development of a rational synthesis strategy for inorganic nanomaterials.

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Section: Remarks On the Role Of The Organicsmentioning

confidence: 99%

Nonaqueous Sol–Gel Routes to Metal Oxide Nanoparticles

2007

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“…There exist several approaches to produce nanoscale materials: vapor-liquid-solid growth [1], solvothermal route [2], Langmuir-Blodgett technique [3], template method [4][5], electrospinning [6], and colloidal chemistry [7]. The most common methods to synthesize tungstite/tungsten oxide are electrochemical [8], solution-based colloidal [9], bioligation [10][11], chemical vapor deposition [12][13], and hydrothermal (HT) [14][15]. A simple heat-treatment of tungstite (WO 3 .H 2 O) allows for the phase transformation to tungsten oxide (WO 3 ), an important class of n-type semiconductors with a tunable band gap of 2.5-2.8 eV [16].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of tungstite (WO3·H2O) nanoleaves and nanoribbons

Ahmadi

Guinel

2014

Acta Materialia

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An environmentally benign method capable of producing large quantities of materials was used to synthesize tungstite (WO 3 .H 2 O) leaf-shaped nanoplatelets (LNPs) and nanoribbons (NRs). These materials were simply obtained by aging of colloidal solutions prepared by adding hydrochloric acid (HCl) to dilute sodium tungstate solutions (Na 2 WO 4 .2H 2 O) at a temperature of 5-10 o C. The aging medium and the pH of the precursor solutions were also investigated. Crystallization and growth occurred by Ostwald ripening during the aging of the colloidal solutions at ambient temperature for 24 to 48hrs. When dispersed in water, the LNPs and NRs take many days to settle, which is a clear advantage for some applications (e.g., photocatalysis). The materials were characterized using scanning and transmission electron microscopy, Raman and UV/Vis spectroscopies. The current versus voltage characteristics of the tungstite NRs showed that the material behaved as a Schottky diode with a breakdown electric field of 3.0x10 5 V.m -1 . They can also be heat treated at relatively low temperatures (300 o C) to form tungsten oxide (WO 3 ) NRs and be used as photoanodes for photoelectrochemical water splitting. Environmental applications can also benefit from WO 3 as a visible light photocatalyst to generate OH radicals for bacteria destruction [35] and photocatalytic reduction of CO 2 into hydrocarbon fuels [36]. The production of leaf-like WO 3 using a metallic tungsten surface exposed to a laser irradiation followed by an aging process has already been reported [37]. However, to the best of our knowledge, this is the first time that a very simple, inexpensive and environmentally benign synthesis of tungstite leaf-shaped nanoplatelets (LNPs) and nanoribbons (NRs) using colloidal chemistry is reported. Two steps are necessary to obtain these tungstite materials: The tungstate ions from sodium tungstate solutions (Na 2 WO 4 .2H 2 O) are first protonated and in a second step, dimerization and crystallization occur. The materials obtained were characterized using scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), UV/Vis, Raman and dynamic light scattering (DLS) spectroscopies. Moreover, the electrical properties of these materials were tested. Keywords

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“…They could detect NO 2 in the range of parts per billion at 180°C. Sensors made of WO 3 nanowires formed by using soft chemistry indicated high sensitivities to NO 2 in the range of parts per billion at 150°C (Polleux et al, 2006). In our study, WO 3 nanowires were formed by the vapor transport method using WO 3 powder as a raw material.…”

Section: Wo 3 Nanowires Formed By Vapor Transportmentioning

confidence: 79%

Formation of Oxide Nanowires by Thermal Evaporation and Their Application to Gas Sensors

Yamazaki¹

2011

Nanowires - Implementations and Applications

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Template‐Free Synthesis and Assembly of Single‐Crystalline Tungsten Oxide Nanowires and their Gas‐Sensing Properties

Cited by 338 publications

References 49 publications

Nonaqueous Sol–Gel Routes to Metal Oxide Nanoparticles

Nonaqueous Sol–Gel Routes to Metal Oxide Nanoparticles

Synthesis and characterization of tungstite (WO3·H2O) nanoleaves and nanoribbons

Formation of Oxide Nanowires by Thermal Evaporation and Their Application to Gas Sensors

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