Preparation of SnO2 whiskers via the decomposition of tin oxalate

Abstract

A new method for preparing SnO 2 whiskers by the decomposition of SnC 2 O 4 is suggested. A Whisker-like morphology of a SnC 2 O 4 precipitate was attained via the gradual addition of an oxalic acid solution to a hot SnCl 2 aqueous solution (T > 50 • C). In comparison, when the solution temperature was either lower than 50 • C or when ethanol was used as the solvent, the SnC 2 O 4 precipitate showed an angular and relatively isotropic morphology. The morphology of the SnC 2 O 4 precipitate remained even after its thermal decomposition into SnO 2 at 400 • C indicating that SnC 2 O 4 precipitation is a key step in preparing the whiskers. The formation mechanism of SnO 2 whiskers was explained by the supersaturation during the precipitation of SnC 2 O 4 .

Thermal Decomposition of Tin(II) Oxyhydroxide and Subsequent Oxidation in Air: Kinetic Deconvolution of Overlapping Heterogeneous Processes

“…18,19 The traditional solid-state synthesis method, which involves the thermal decomposition and oxidation of a precursor Sn(II) compound in an oxygen-rich atmosphere, also remains worthwhile as a cost-effective, large-scale process. For example, the oxidative decomposition of crystalline SnC 2 O 4 has been examined as a possible synthesis method for nanosized and microstructural SnO 2 , 4,30−38 including porous nanorods, 30,31,37 whiskers, 32 and flowerlike and hierarchical constitutions. 4,33 However, controlled synthesis of SnO 2 via oxidative decomposition of Sn(II) compounds is challenging.…”

“…Various synthetic methods for the preparation of morphologically controlled SnO 2 have been examined with the objective of identifying additional sophisticated functional properties of this n -type wide-bandgap semiconductor , that will enable other potential applications, such as gas sensors, − anode materials for lithium-ion batteries, − transparent thin-film electrodes, − optoelectronic devices, − and photocatalysts. , The majority of these synthetic methods are wet-chemical processes, sometimes facilitated by sol–gel, hydrothermal, ,,,,,− ,, microwave-assisted, sonochemical processing, dip-coating, and spray pyrolysis techniques. , The traditional solid-state synthesis method, which involves the thermal decomposition and oxidation of a precursor Sn­(II) compound in an oxygen-rich atmosphere, also remains worthwhile as a cost-effective, large-scale process. For example, the oxidative decomposition of crystalline SnC 2 O 4 has been examined as a possible synthesis method for nanosized and microstructural SnO 2 , ,− including porous nanorods, ,, whiskers, and flowerlike and hierarchical constitutions. , …”

Deposition efficiency in the preparation of ozone-producing nickel and antimony doped tin oxide anodes

“…Wang et al [16] used ammonia and oxalic acid to prepare their precursor, probably forming oxalates [30,31]. These salts should not evaporate [32][33][34] and thereby the problem of enrichment due to loss of precursors during heating is probably avoided.…”

Physico-Geometrical Mechanism and Overall Kinetics of Thermally Induced Oxidative Decomposition of Tin(II) Oxalate in Air: Formation Process of Microstructural Tin(IV) Oxide

“…The morphological characteristics of the as-produced SnO 2 vary depending on the particle size and morphology of the SnC 2 O 4 precursor. SnO 2 particles with different morphologies, such as porous nanorods, 25,26,32,33 whiskers, 27 flower-like, and hierarchical construction, 2,28 have been synthesized by the thermally induced oxidative decomposition of shape-controlled SnC 2 O 4 , in which the solid products are composed of SnO 2 nanoparticles. Notably, SnO 2 produced by the oxidative decomposition of SnC 2 O 4 exhibits morphological characteristics, which are peculiar to solid product, imparted by the solid−gas reactions, in which gases act as both reactant and product.…”

“…This study attempted to identify the physico-geometrical events occurring during the thermally induced oxidative decomposition of SnC 2 O 4 in air. Two SnC 2 O 4 samples with different morphological characteristics were prepared using previously reported methods. , The oxidative decomposition processes of the samples were systematically traced by the mass-change measurements under isothermal, linear nonisothermal, and controlled transformation rate thermal analyses (CRTA) conditions using thermogravimetry (TG). The reaction pathway and behavior of each sample were interpreted by analyzing the evolved gas and crystalline phase change during the reaction.…”