Oxidative decomposition means that if titanium oxide is exposed to light, organic substances on its surface will be broken down by oxidation, eventually forming carbon dioxide and water. This has applications in fields such as deodorization, elimination of volatile organic compounds (VOCs), elimination of soiling, antibacterial action and sterilization.
Titanium oxide is said to be an optical semiconductor, and it changes from an insulator to a conductor by absorbing the energy of light. This occurs because electrons are excited from the valence band to the conduction band, causing the formation of holes in the valence band . The Excited electrons react with oxygen in the atmosphere Anions forming superoxide (O • two -), and the holes react with Moisture in the atmosphere producing Hydroxyl Radicals (• OH). These are Extremely Active Species reactive oxygen, and decompose and Oxidize Organic Substances ( Figure 1 ).