Synthesis and characterization of crystalline tin oxide nanoparticles

Abstract

Monodisperse non-aggregated spheroidal nanoparticles of SnO 2 cassiterite are prepared through hydrolysis of tin isopropoxide in the presence of acetylacetone and p-toluenesulfonic acid, followed by ageing at 60 uC. The obtained sols remain stable for several months at 4 uC. The nanoparticles have been characterized in the solid state (xerosol) by powder X-ray diffraction, TEM, FTIR, TGA-DTA, and 119 Sn MAS and 13 C CP-MAS NMR. The mean size of the cassiterite oxide core is about 1-2 nm. These particles do not aggregate in suspension because their surfaces are protected by an hybrid organic-inorganic layer containing acetylacetonate ligands, acetylacetone, p-toluenesulfonates and water.

Effect of Sintering Temperatures on the Synthesis of SnO2 Nanospheres

“…The strong acidic condition enhances the hydrogen bonding among the protonated nanocrystallites leading to a high degree of agglomeration among freshly prepared nanocrystallites. The chelated tin has six-fold coordination available for reacting while 4 fold is available in an inorganic starting material so its reactivity is greatly lowered [34,35]. The general formula is M(OOR)n (M-refers to Sn), and when sol was refluxed at 373 K, the solution changed slowly into gel; the controlled sol-gel process can be described as follows [36]:…”

Respuesta eléctrica de películas gruesas del sistema SnO₂-TiO₂, conformadas con polvos cerámicos obtenidos a través del método pechini

“…Las propiedades eléctricas de los cerámicos policristalinos de SnO 2 dependen fuertemente de la química de defectos que pueda ocurrir en ellos, las cuales se ven afectadas por el método de síntesis del polvo cerámico, la temperatura y la atmósfera utilizada para realizar el tratamiento térmico del compuesto. Considerando concretamente la síntesis de los polvos cerámicos de SnO 2 , puro o dopado, los métodos mas importantes utilizados para obtenerlos son: sol-gel (8)(9)(10), método de precipitación homogénea (11), precipitación controlada (12,13), precursor polimérico (4), y reacciones en estado sólido a través de la descomposición de carbonatos (12).…”

The evolution of crystalline ordering for ligand-ornamented zinc oxide nanoparticles

“…48 Strong complexing ligands (SCL) such as carboxylic acids (ac, cit), beta-diketones (pent, dmlt) and allied derivatives result in the formation of new precursors M(OR) n−x -(SCL) x , which are less hydrolysable and thus alter the nucleation and crystallization. 49 For zirconia in propanol, polydisperse disordered particles were shown to form at high hydrolysis ratios in presence of acetylacetone as ligand. 44 The crystallization of such disordered intermediated can be promoted at elevated temperatures, e.g.…”

“…under hydrothermal conditions, where reorganization and reprecipitation to equilibrium conditions is favoured. 47,49 This applies to the fast crystallization observed recently in situ for yttria-stabilized zirconia in supercritical methanol. 19 In contrast to these experiments, the ambient conditions chosen within this study, slow down the crystallization and are thus very suitable to distinguish changes to the crystallization kinetics induced by the different ligands.…”

“…As an amorphous network forms, bonds which are once formed, cannot disintegrate immediately, but exist over certain time scales before they restructure to the energetically more favourable crystalline state. [46][47][48][49] The chosen solvent, ligand and degree of supersaturation influence the ratio of dense particles and branched chains. 48 Strong complexing ligands (SCL) such as carboxylic acids (ac, cit), beta-diketones (pent, dmlt) and allied derivatives result in the formation of new precursors M(OR) n−x -(SCL) x , which are less hydrolysable and thus alter the nucleation and crystallization.…”