[Brief]
photocatalyst can remove efficiently coliform, yellow staphylococcus, purulence bacteria and so on. Meantime has more powerful oxidation ability than ozone and negative oxygen ion. It also can decompose odor source. More ever, photocatalyst has powerful hydrophilic ability and keep off contamination to attach , can keep new building clean for a long time . Also it is innoxious and safe...
In present polluted environment, A new kind of Photocatalyst technology has been favorable increasingly. Photocatalyst improves people life with complete antibacterial ability and no pollution, especially in room and car purification. It is most ideal material for improving room environmental pollution in the world.
What is photocatalyst?
Photocatalyst is compounded by photocatalyst. It is general name of semiconductor material represented by nanometer titanium dioxide (TIO2) with light catalyzing function. After TiO2 absorbs ultraviolet light, inter electron is stirred up and formed into powerful oxide and hydroxide radicals. It has powerful oxidation ability, so it can destroy bacterial cell membrane, solidify virus protein and restrain virus's activity. Its killing bacteria ability can reach 99.9%. TiO2 activates absorbed oxygen and moisture and occur free radicals (-OH) and (-O2) which can turn organic substance and harmful air into water and carbon dioxide so as to purify air. At the moment, chain degradation reaction occurs between the free radicals and kinds of contaminant each other.
According to lab test, photocatalyst can remove efficiently coliform, yellow staphylococcus, purulence bacteria and so on. Meantime has more powerful oxidation ability than ozone and negative oxygen ion. It also can decompose odor source. More ever, photocatalyst has powerful hydrophilic ability and keep off contamination to attach , can keep new building clean for a long time . Also it is innoxious and safe.
Photocatalyst technology originates from Japan. In 1972, professors Fujishima and Dr.tengdaozhao in Tokyo University discover that radiating TiO2 electrode with light can electrolyses water, it is called famous Honda-Fujishima Effect. After researched for 30 year basing on this principle, photocatalyst research made a great breakthrough. This technology has reached industrial demand and be applied widely. Now TiO2 has been transformed into powder, solution, gel and paint material in present industrial condition and is widely applied in fields like sterilization, deodorization, preventing contamination and cleaning air .
Efficacy of Photocatalyst
According to lab test of European and American Authority Organization, comparing with other deodorants, the deodorant ability of photocatalyst in each square centimeter is 150 times as high capacity fiber, and far more stronger than active carbon fridge deodorants. Additionally, TiO2 was treated specially and plated on surface of glass to prevent contamination and clean itself. After treated by photocatalyst original liquid , the object can extend its usage life and keep its efficacy for long.
Relative to traditional sterilization method, Photocatalyst product has more advantages. Because free radicles from TiO2 radiated by ultraviolet has powerful oxidation and can react with organic substance, benzene and ammonia, so it can antisepsis, deodorize, rid oil and prevent fog, even it can prevent ultraviolet. Photocatalyst product has morefull, high efficient and standing purifying advantage compare with traditional antisepsis method . The last but not the least, it does no harm to body, because final outcome of reaction is water and carbon dioxide. This is the most advantage comparing to traditional chemical and ultraviolet sterilization.
China Room Decorating Association' testing report of Photo catalyst products showed that sterilization rate to coliform, yellow staphylococcus, corps bacteria and other harmful bacteria is all above 99%, The decomposing rate to formaldehyde and volatility organic compound substance in 24 hours respectively reach 77% and 74%.
Photocatalyst has long term efficacy. Because nanometer TiO2, only as catalyst, don't react in course of oxidation and deoxidize reaction and lost nothing. So its effect time is often above 10 years .
Reaction Mechanism
When the micro-particle of nanostructured Titanium Dioxide(TiO2) is exposed by the 388nm UV light, its inner will stir up hole-electron pair ,and the hole-electron pair will quickly remove to its surface and activate absorbed oxygen and moisture and occur free radicals (-OH ) and active oxygen (-O2). At the moment, chain degradation reaction occurs between the free radicals and kinds of contaminant or bacteria each other. For strong oxidation, the photo catalyst can implement the function of anti-bacteria by destroying the cell membrane. Specific detail reaction is like this, after titanium dioxide (TiO2) absorbs sun light, it is formed to be electronegative high active electron e- , and positive hole h+. With effect of electric field, electron e- and hole h+ are separated and moved to surface of particle. According to energetic theory, h+ can oxygenates OH- and H2O conglutinated on surface of TiO2 into free radicle. More ever, free radicle has strong oxidation ability and can oxygenate and decompose various organic substance(e.g. Formaldehyde ,Benzene ,TVOC), bacteria and part inorganic contamination (Ammonia, NOx)into no harmful substance: CO2 ,H2O . OH Free radicle has no selectivity to reactant, so it makes crucial effect in photo catalyzing . Meanwhile, high active electron e- has strong deoxidize ability and can deoxidize oxygen in air .
Application
Photo catalyst has been applied successfully to car antibacterial and air clean filed. It is evangel for modern drivers. photo catalyst can be used to remove efficiently irritative odor of new car. In Japan, there are more than 20,000cars treated by photo catalyst. In hospital, photo catalyst can kill bacteria on sickbed and appliance and no drug-fast bacteria left. Many families also use photo catalyst to kill bacteria to prevent illness. The relevant products are gargle, toothpaste, chewing gum, contact lens cleaning liquid, keeping fresh bag , flower living keeper and so on , which has a large market. With increase of people's environmental protection consciousness and society's advancement, Photo catalyst material will be applied gradually in various fields.
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