Inquiry Tungsten Trioxide Infrared Absorption Property

Nano tungsten trioxide is a kind of catalysis semiconductor functional materials; it has stealth features, electrochromic, photochromic gas, light-induced color multifunction, gas, superconductivity, and many other characteristics. Numerous studies show that the surface plasmon resonance can produce semiconductor materials and absorbing specific wavelengths of light. Tungsten oxide nanoparticles increase in certain third phase reduction treatment or cationic, it is capable of accumulating a large amount of free electrons on its surface, so that it has a plasma resonance absorption characteristic of near-infrared light. Since tungsten oxide under anoxic conditions can generate stable Magneli phase and cubic and hexagonal, tungsten structure introducing green copper cations that can form a stable. Therefore, when the reduction treatment can be introduced by a large number of free electrons, tungsten oxide and composite still has a stable structure and physico-chemical properties, and it can remain stable absorption properties in the long sunlight.

Since tungsten oxide nano powder does not have near-infrared absorption of sunlight, it needs to be subjected to reduction treatment to WO_3-x. We take nanometer tungsten trioxide as starting material in a reducing atmosphere, sintering it 1 h at 350--550 ℃ the [volume ratio V (H₂): V (N₂) = 1: 9], then stop input H₂, N₂ under protection. The temperature was raised to 800 ℃, and heated at this temperature for 1 h, and then turn off the power so that the temperature dropped to room temperature to obtain WO_2.92 and WO_2.83. we can find that XRD peak becomes sharp with increasing temperature, the smaller the size of the nanoparticles at lower temperatures, the crystallization is not complete, as the temperature increases, the particle size becomes larger, the corresponding is more complete due to crystallization. The size of the nano-tungsten oxide particles is much smaller than the wavelength of visible light, visible light can maintain transparency.

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