What is a Photocatalyst? Photocatalyst Because of its characteristics of titanium oxide, strong oxidative decomposition occurs at the surface of the place where light energy of being like sunlight or room light hits and then various materials approaching to are broken down. Meanwhile the titanium dioxide itself does not change, so this reaction repeats every time light is received. What is Titanium Dioxide? Titanium Dioxide Titanium dioxide is a white powder (superfine particles) that has long been used as a white pigment. It is used for a wide variety of usages such as in coatings, dental material, toothpaste, and cosmetics. It is also used as a food additive for coloring in white chocolate, sweets, and chewing gums because it is tasteless, odorless, and is harmless to humans. How Photocatalysis Works When Titanium dioxide receives energy from light, electrons (-) are released from the surface. The electrons released are combined with oxygen in the air then creates “O2-” (Superoxide anion). The surface where the electrons were released is tinged with the electric charge of plus, and takes electrons from moisture of the air and then return to its original state. On the other hand, the moisture that lost the electron becomes a hydroxyl radical (•OH). ＊This is referred to as an “Electron hole”, and this is called as 「Hole of plus (Electron hole)」or just a hole. ＊Before reacting with H2O, there are cases where electrons are taken and broken down directly from organic compounds. The “O2-” and “•OH” that resulted in a process of transfer of this electron can produce strong oxidative decomposition, which decompose organic compounds such as oil causing dirt and adhesion, bacteria, harmful chemical gas, viruses, and molds even into simple harmless substances that then are released into air.
Posted on: Thu, 04 Jul 2013 00:30:21 +0000
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