Date :January, 2000 file=CE-107-01
Copyright :Copyright 2000 Chemical Week Publishing, LLC Volume :107 Issue :1 Page :17-25 Section :CHEMENTATOR
Photosensitive catalyst sees the light
Edited by Gerald Parkinson
The anatase form of titania can be used as a photosensitive catalyst for oxidation and reduction reactions, but its capability is limited because it is activated only by the absorption of ultraviolet light. Now, a titania catalyst that is activated by visible light -- about 45% of the light energy from the sun -- has been developed by EcoDevice Co. (Tokyo; 731) in cooperation with Kinki University (Higashi-Hiroshima).
The catalyst is made by reducing titania at just below 500°C, using a 100 - 500 W microwave plasma for 1060 min. The process takes place under hydrogen gas flow at 12 Torr.
In tests, the new catalyst has decomposed aldehydes almost twice as fast as a conventional titania catalyst, the company says. Also, it has achieved 20% destruction of oxides of nitrogen (NOx) with visible light, versus 5% for conventional titania, without sacrificing the normal oxidation efficiency of 35-40% with UV light.
EcoDevice will start marketing the new catalyst in April from a 1.2-m.t./yr pilot plant. The price will be around $300/kg.