Hybrid Nanostructures Obtained by Transport and Condensation of Tungsten Oxide Vapours onto CNW Templates

Abstract

We present hybrid nanomaterial architectures, consisting of carbon nanowalls (CNW) templates decorated with tungsten oxide nanoparticles, synthesized using a mechanism based on tungsten oxide sublimation, vapor transport, followed by vapor condensation, in the absence or presence of plasma. The key steps in the decoration mechanism are the sublimation of tungsten oxides, when are exposed in vacuum at high temperature (800 °C), and their redeposition on colder surfaces (400–600 °C). The morphology and chemical composition of the hybrid architectures, as obtained from Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy, are discussed with respect to substrate nature and the physical conditions of synthesis. We pointed out that the decoration process is strongly dependent on the temperature of the CNW templates and plasma presence. Thus, the decoration process performed with plasma was effective for a wider range of template temperatures, in contrast with the decoration process performed without plasma. The results are useful for applications using the sensing and photochemical properties of tungsten oxides, and have also relevance for fusion technology, tungsten walls erosion and material redeposition being widely observed in fusion machines.

In vitro analysis of the cytotoxic effect of two different sizes ITER-like tungsten nanoparticles on human dermal fibroblasts

“…Despite its nowadays intensive use in the nanotechnology, engineering field [ [47] , [48] , [49] , [50] , [51] ] and in fusion technology, W involves a potential occupational or accidental risk. In particular, when thermonuclear fusion reactors, like ITER, become operational, W dust could represent a potential risk for environmental safety and for human health as they might be released in case of accidental situations, such as LOVA.…”

Regulating NIR reflecting property of hydrothermally synthesized tungsten oxide nanostructures via calcination

“…It is evident that the particles have non-uniform size and are homogeneously distributed. Furthermore, the onset of Ostwald ripening, a process where smaller particles evaporate and redeposit on the surface of bigger ones at temperatures above 700 °C [31], is seen in figure 3(e), and in figure 3(f) it is prominently seen. In order to validate these results and to get detailed information, transmission electron microscopy (TEM) and high-resolution TEM (HR-TEM) images of two representative tungsten oxide nanostructures (those calcined at 600 and 900 °C) are taken and are given in figures 5 and S3 respectively.…”

Cyanido-Bridged Bimetallic/rGO Electrodes for Dye-Sensitized Solar Cells and Battery-Type Supercapacitors

“…38 Moreover, for the tungsten ion, peaks at 34, 35, and 37 eV binding energies are spotted, which represent the core peaks of W 4f 7/2 and W 4f 5/2 having the W 4+ state with an extra low-intensity peak at 34 eV (Figure 3c). 39,40 Likewise, on deconvoluting the XPS spectra of the sulfur element, there are five peaks obtained, attributed to S 2p 3/2 and S 2p 1/2 spin− orbits (Figure 3d). The peaks with binding energies of 164, 165, 166, 168, and 170 eV confirm the occurrence of metal-S, S=O, S−S, and two C−S bonded sulfur ions.…”