Tantalum Tungsten Bronze

Introduction

Tungsten oxide is a kind of transition metal oxide, its special property makes it be widely used in electrochromic device, gas sensor, separating material and so on. W ion in tungsten bronze belongs to changeable valence state, when introduce transition metal into crystalline structure, valence state of W transits between Ｗ６＋，Ｗ５＋ and Ｗ４＋, unstable oxygen valance will form in lattice, surface of material will show defects. As a result, tungsten oxide shows special physical and chemical property. Tantalum belongs to transition metal which can be used as electrode material. Also dimension of Ta5+ is small and active, we can judge that doping tantalum can have great influence on its electric chemical property.

Preparation

1. Weighing 2g Na₂WO₄.2H₂O in reaction still with politef lining. Add in redistilled water, magnetic stirring and dissolving.
2. Adding a certain amount of 3 mol/L hydrochloric acid, control the whole reaction system pH lower than 1.5. Adding 0.05 mol/L TaCl₅ and 0.5 mol/L NH₄(SO₄)₂, stirring for 2 hours and sealed the reaction still.
3. Heating it for 48h under 170 ℃, wash the reaction producer with distilled water to neutral, then put it in －40℃ lyophilizer.