Controlled synthesis of tungsten trioxide with globular clusters constructed of nanoplates by rapid breakdown anodization

Abstract

Herein, the electrochamical synthesis of tungsten trioxide (WO3·H2O) with globular clusters constructed of nanoplates is demonstrated. On applying a breakdown anodization potential of 25 V at 50 °C, tungsten foil anode is efficiently electro-oxidized into WO3 globular clusters constructed of nanoplates powder, instead of a thin film structure as conventional anodization occurs. The resulting globular clusters were characterized using SEM, TEM, and XRD. The effect of the composition of electrolyte on the breakdown anodization of the W substrate is discussed. And we suggest that the growth of the nanoplates is initiated by localized anodic dielectric breakdown, followed by a effectively crystal growth in electrolyte at high breakdown field.

Sodium Dodecyl Sulfate-Adjusted Phase Composition of Hydrated Tungsten Oxides as Stable Self-Supporting Electrodes for Supercapacitors with High Volumetric Specific Capacitance

“…The heat that drives the dehydration can be provided by several ways, such as direct annealing at 120 °C, 4,8 increase of reaction temperature, 15 or enhancement of localized electric field that produces large amounts of Joule heat. 16 In the abovementioned synthetic methods, additives such as acids, complexing agents, ligands, and surfactants are often utilized to control the morphology and/or size of the WO 3 •xH 2 O products. 17 addition of varying amounts of HCl in an acidic precipitation method.…”

“…Our group has previously reported a rapid breakdown anodization method to prepare WO 3 ·2H 2 O and WO 3 . , This method is one of the simplest to synthesize nanostructured WO 3 · x H 2 O and the morphology of the products can be easily tuned by parameters such as the electrolyte composition, applied voltage, temperature, and anodization time. Nevertheless, the products obtained by this method are in the form of powders and thus need to be mixed with binders and conductive agents to fabricate supercapacitive electrodes.…”

“…On the contrary, WO 3 ·H 2 O is normally obtained by thermal dehydration of WO 3 ·2H 2 O. The heat that drives the dehydration can be provided by several ways, such as direct annealing at 120 °C, , increase of reaction temperature, or enhancement of localized electric field that produces large amounts of Joule heat . In the above-mentioned synthetic methods, additives such as acids, complexing agents, ligands, and surfactants are often utilized to control the morphology and/or size of the WO 3 · x H 2 O products. − For example, Yang et al have achieved morphology-controllable synthesis of vertically aligned plate-like arrays of WO 3 ·H 2 O via using (NH 4 ) 2 C 2 O 4 as a capping agent .…”