Today we know a lot of chemical reactions, the flow of which depends not only on the composition of the reactants, as on their physical condition.
Many of them impossible without certain conditions.
For similar type of reaction are, and photocatalysis.
In a broad sense, it is a photocatalysisprocess repeated (from thousands to millions of times) the acceleration of chemical reactions with simultaneous exposure to the catalyst substance and light emission. Photocatalysis feature consists in the fact that separate light radiation effect on the reagents or catalyst does not have any significant effect.
There are several types of photocatalysis. In photoinduced catalysis increase the reaction rate provided by the catalyst, which is formed from a previously inactive agent (prekyusora) under the influence of light. Under certain conditions, these reactions can go after the termination of exposure.
Photoactivated catalysis similar to catalysisphotoinduced (it also prekyusora formed from the catalyst by exposure to light). However, during the course of the primary reaction, the catalyst is reconverted to prekyusor. It is therefore necessary to ensure a constant irradiation of catalysis.
Catalytic photoreaction as a kind ofphotocatalysis characterized in that the catalyst in the traditional role played by them. Under the influence of light is changed reactants by passing the so-called excited state. It becomes possible to effectively their interaction with the catalyst. Accordingly, the reaction occurs only under the influence of light.
Photocatalytic reactions are quite commonin nature. The most striking example of natural photocatalysis is the photosynthesis. In the chemical industry today photocatalysis is used very widely. With it, various accelerated oxidation, reduction, hydrogenation and dehydrogenation of polymerization, precipitation of metals. Based on the effect of photocatalysis produce air purification system.</ P>