Potassium tungsten bronze (KxWO3) may be prepared by hybrid microwave method using K2WO4, WO3 and W powder as raw materials. With the increase of nominal potassium content x, the crystal structure of KxWO3 transforms from hexagonal (0.20≤x≤0.33) to tetragonal (0.50≤x≤0.60). The tetragonal potassium tungsten bronze show metallic behavior. The hexagonal potassium tungsten bronze show semiconducting behavior and the charge density wave (CDW) transition is observed in K0.22WO3 around 265K. The KxWO3 has two types of crystal structure, hexagonal structure and…

Sodium tungsten bronze (NaxWO3, 0<X<1) may be prepared by low temperature hydrothermal synthesis method. Low Temperature Hydrothermal Synthesis of Sodium Tungsten Bronze 1. Add dilute hydrochloric acid to 0.25 mol•L-1 Na2WO4 solution dropwise under stirring until the pH is around 6.5. 2. The NaBH4 solution was dropped into the Na2WO4 solution at a rate of 2~4d/s. 3. Keep the pH of the solution at 6.5±0.2 by adding dilute hydrochloric acid dropwise. 4. The obtained dark green suspension was allowed to…

Hydrogen tungsten bronze (HxWO3, 0≤x≤1) may be used as a co-catalyst in combination with platinum, thereby reducing the usage amount of platinum (The cost of platinum is high) and increasing the catalytic activity of platinum. Hydrogen tungsten bronze combines with the adsorbed hydrogen which has not been completely dissociated on platinum surface, thus increasing the rate of hydrogen oxidation reaction. At the same time, HxWO3 has the ability to provide protons after accepting a large number of protons. These protons…

Platinum-hydrogen tungsten bronze may be applied as catalyzer. The Electroxidation of Methonal on Platinum-hydrogen Tungsten Bronze Direct methanol fuel cells (DMFCs) have been studied extensively due to their low operating temperature (<1008°C) and the fast start-up for applications such as portable and stationary power sources and electric vehicular applications. However, slow kinetics of methanol oxidation is one of problems that retard the practical application of DMFCs. Recently, semi-conductive metal oxides such as WO3, MoO3, and V2O5 were considered as a…

Tantalum tungsten bronze (TaxWO3) may be synthesized via hydrothermal method using TaCl5 and Na2WO4•2H2O as raw materials. The TaxWO3 synthesized at 170°C for 48h is hexagonal with the size of about 10~50nm. And TaxWO3 has a strong electrocatalytic activity for hydrogen evolution reaction. The morphology, crystal structure and optical properties of synthesized products were characterized by means of XRD, TEM, SEM, UV-vis and Raman technologies. In addition, the electrocatalytic activity for hydrogen evolution reaction was also investigated by cyclic voltammetry.…