Because the power of light promotes the oxidative decomposition reaction, titanium oxide in this phenomenon is later called photocatalyst. This phenomenon is equivalent to converting light energy into chemical energy. At that time, in the context of the oil crisis, the world was looking forward to finding new energy sources, so this technology attracted attention as an epoch-making method to extract hydrogen from water. However, it is difficult to extract a large amount of hydrogen in a short time, which cannot be used for the development of new energy, so the temperature drops rapidly after the sensation.
1992 the first international symposium on titanium dioxide photocatalyst was held in Canada. Japanese research institutions have published many new ideas about photocatalyst and put forward research results applied to nitrogen oxide purification. Therefore, the number of patents related to titanium dioxide is also the largest, and other catalyst connection technologies cover catalyst preparation process, catalyst structure, catalyst carrier, catalyst fixation method, catalyst performance test and so on. Taking this as an opportunity, the research on the application of photocatalyst in antibacterial, antifouling and air purification fields has increased sharply. From 197 1 to June 2000, a total of10,717 patents related to photocatalyst were filed. The wide application of titanium dioxide TiO 2 photocatalyst will bring people a clean environment and healthy body.
The length of the object is 10 -6 meters, which is called micrometer (micron; Mm), 10 -9 meters is called nano (nano; Nm). Various application materials will gradually enter the nano era from micron. Nano-materials are composed of particles with the particle size of 1~ 100nm. The particle size is extremely fine and the specific surface area is very large. With the decrease of particle size, the percentage of surface atoms increases. The phenomenon of high surface energy is caused by incomplete coordination of a large number of atoms on the surface. The ratio of surface energy to total energy is greatly increased, which makes nano-materials have the characteristics of adsorption, light absorption and melting point change. Using the technology and characteristics of nano-ultrafine particles, the material itself has been developed, which does not participate in the reaction at all, but can promote and improve the reaction energy. The catalytic technology of catalyzing the target reaction is applied to environmental cleaning, and harmful or toxic substances are accelerated to become stable and harmless substances, thus achieving environmental protection effects.
Nano-titanium dioxide photocatalyst is a substance that can promote chemical reactions without changing itself under the irradiation of light, just like chlorophyll in plant photosynthesis. Under the irradiation of sunlight or indoor fluorescent lamp, TiO2 _ 2 photocatalyst can produce antibacterial, deodorizing, oil pollution decomposition, mildew and algae prevention and air purification functions.