Synthesis of Tin and Tin Oxide Nanoparticles of Low Size Dispersity for Application in Gas Sensing

Abstract

Nanocomposite core-shell particles that consist of a Sn0 core surrounded by a thin layer of tin oxides have been prepared by thermolysis of [(Sn(NMe2)2)2] in anisole that contains small, controlled amounts of water. The particles were characterized by means of electronic microscopies (TEM, HRTEM, SEM), X-ray diffraction (XRD) studies, photoelectron spectroscopy (XPS), and Mossbauer spectroscopy. The TEM micrographs show spherical nanoparticles, the size and size distribution of which depends on the initial experimental conditions of temperature, time, water concentration, and tin precursor concentration. Nanoparticles of 19 nm median size and displaying a narrow size distribution have been obtained with excellent yield in the optimized conditions. HRTEM, XPS, XRD and Mossbauer studies indicate the composite nature of the particles that consist of a well-crystallized tin beta core of approximately equals 11 nm covered with a layer of approximately equals 4 nm of amorphous tin dioxide and which also contain quadratic tin monoxide crystallites. The thermal oxidation of this nanocomposite yields well-crystallized nanoparticles of SnO2* without coalescence or size change. XRD patterns show that the powder consists of a mixture of two phases: the tetragonal cassiterite phase, which is the most abundant, and an orthorhombic phase. In agreement with the small SnO2 particle size, the relative intensity of the adsorbed dioxygen peak observed on the XPS spectrum is remarkable, when compared with that observed in the case of larger SnO2 particles. This is consistent with electrical conductivity measurements, which demonstrate that this material is highly sensitive to the presence of a reducing gas such as carbon monoxide.

Mn3O4 Nanoparticles: Synthesis, Characterization, and Dielectric Properties

“…X-ray structural analyses confirmed that Mn 3 O 4 nanoparticles are found to be slightly temperature dependent at higher frequency. These results indicate that the dielectric properties showed a usual dielectric dispersion explained on the basis of the Maxwell-Wagner model.…”

“…Metal oxide nanocrystals are widely applied in catalysis, energy storage, magnetic data storage, sensors, and ferrofluids [1][2][3][4]. Tetramanganese oxides (Mn 3 O 4 ) are particularly used as main sources of ferrite materials [5] and applied in numerous industrial fields such as magnetic [6], electrochemical [7], and catalysis [8,9].…”

Investigation on Structural, Surface Morphological and Dielectric Properties of Zn-doped SnO2 Nanoparticles

“…These defects bring on additional electronic states in the band gap, which can mix with the intrinsic states to a substantial extent and which may influence the spacing of the energy levels and the optical properties of nanopowders. A variety of methods were used to prepare SnO 2 nanostructures, such as hydrothermal method, polymeric and organometallic precursor synthesis, soncation procedure, microwave synthesis and surfactant-mediated method [8][9][10][11][12][13][14][15][16][17][18] . Zinc is a quite active element.…”

Organometallic approach for platinum and palladium doping of tin and tin oxide nanoparticles: structural characterisation and gas sensor investigations

“…[26][27][28][29][30][31][32][33] We have shown that this methodology can be extended to the synthesis of nanoparticles of metal oxides with a precise control of morphology. [34][35][36][37] which can be, in a second step, oxidized into well crystallized nanoparticles of the corresponding oxides, without coalescence. We recently reported a direct organometallic route to prepare ZnO colloidal solutions containing nanoparticles of controlled size and shape.…”