Tungsten Oxide Nanoribbon Arrays

Tungsten oxide is a new functional material, which can be used in chemical sensors, catalytic materials, electrochemical electrodes, electrochromic materials, high temperature superconducting materials, solar energy absorbing materials, wave absorbing stealth materials and so on.

In recent years, nanostructured materials have attracted great interest in the synthesis of tungsten oxide nanostructured materials due to their structure-size effects and high surface area. Some nanostructures of tungsten oxide (such as nanorods, nanofibers, nanowires, and nanometers) tubes, nanoneedles, and dendritic structures have been successfully prepared, and the methods used are generally classified into liquid phase synthesis and vapor phase deposition.

At present, there are some problems in both liquid phase synthesis and vapor deposition methods: for example, it is impossible to obtain orderly nanoribbon-structured tungsten oxide materials which can be directly grown on tungsten substrates, the involvement of exogenous gases or reagents in the preparation process, or the lack of large-scale precision reaction equipment, etc. In order to improve and solve the above problems, researchers proposed a tungsten oxide material with nanoribbon array structure, which was obtained by oxidation reaction between tungsten metal and oxygen in air. The main processes of preparing tungsten oxide nanoribbon array structure materials include:

1.The tungsten wire is fixed at both ends of the positive and negative terminal of the heating power supply, and the reaction chamber is sealed.

2.Pump the pressure of the reaction system to 4000Pa with a rotary vane vacuum pump, then close the vacuum pump. Turn on the heating power, increase the heating current slowly, control the temperature of the matrix at 500 ℃, keep the heating current stable and react for 30 minutes.

3.Turn off the heating power, keep the vacuum of the reaction chamber unchanged, cool to room temperature naturally, open the reaction chamber and take out the samples.

4.The materials were analyzed by scanning electron microscopy, transmission electron microscopy and X-ray diffraction.

The results show that tungsten oxide nanoribbon arrays can be grown perpendicular to the matrix direction. The length of a single tungsten oxide nanoribbon is more than 2 microns, the width is 200-400 nanometers, and the thickness is 10-50 nanometers. The banded nanostructures of tungsten oxide materials are arranged neatly and orderly. The banded nanostructured tungsten oxide material belongs to monoclinic tungsten trioxide, which is firmly bound to the matrix, has a large specific surface area and remarkable nano-size effect.

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