Tungsten Trioxide Nano Sheet Preparation by Electrochemical Anodization

Tungsten trioxide and its hydrated oxide are very important n-type semiconductor materials, with band gap between 2.4-2.8ev. They have excellent physical and chemical properties and unique electrocatalytic activity, and have very important applications in electrochromic, gas sensitive, electrocatalytic and photocatalysis fields.

Electrochemical anodizing is a low-cost method which can build regular nanomaterials on a large area. Its basic principle is that the metal or alloy is placed in the corresponding electrolyte as the anode. Under specific conditions and the effect of external electric field, the ion of the electrolyte etches the metal surface of the anode, and gradually accumulates on the surface of the electrode to form a certain morphology and structure of metal oxidation film layer. However, the film is usually thin, single structure, low utilization rate of metal anode, and does not have high economic benefits in industrial production and application.

The process of electrochemical preparation of tungsten trioxide nanoflakes is very simple: the tungsten flakes with thickness of 0.085mm are cut into a specification of 1 × 1cm², washed by ultrasonic in acetone, ethanol and deionized water for 15min respectively, washed by deionized water and dried after drying to prepare the metal tungsten electrode after oil removal; the 1-ethyl-methylimidazolium tetrafluoroborate ([EMIM] BF4) and deionized water are 0.6ml and 12ml respectively Add 47.4ml glycol to get electrolyte (volume fraction of ionic liquid is 1%, volume fraction of deionized water is 20%). Take tungsten sheet as anode, titanium sheet (thickness 0.2mm, specification 2 × 2cm²) as cathode, put it into the electrolyte, keep the electrode spacing of 1.5cm, control the electrolyte temperature of 25 ℃, oxidize to the complete dissolution of tungsten under 20V voltage, and oxidize to powder shape (8h); collect solid powder, remove water to clean, filter and dry, and get the product tungsten trioxide nano sheet.

Based on tungsten metal and in the organic solvent electrolyte containing ionic liquid, nano scale tungsten oxide powder materials were prepared by electrochemical anodization. By controlling the composition of electrolyte, reaction temperature, oxidation voltage and oxidation time, different sizes of nano-sized tungsten oxide were obtained. The prepared tungsten trioxide nanoflakes have regular structure, uniform size, large specific surface area, high output, stable properties, high utilization rate for metal tungsten matrix, high economic benefits, and broad application prospects in industrial applications.

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