One stop catalyst
doi:10.1038/nindia.2008.258 Published online 18 August 2008
New research has devised nano-sized catalysts that help degrade harmful chemicals in the presence of light. Researchers have made nanocomposites of noble metals (platinum and palladium) and titanium dioxide that work better in degrading methyl orange dye than conventional titanium dioxide nanoparticles alone1. The photocatalytic activity of these nanocomposites could play a vital role in disposing harmful chemicals like methyl orange dye.
Noble metal-supported catalysts are widely used in industrial processes such as chemical synthesis, oil refining and exhaust gas treatment. While making catalysts most of the processes use liquid phase methods which require a host of post treatment steps like filtration, drying or calcination. To avoid this and to produce nano-sized catalysts of desired shapes and activities, the researchers resorted to a single step gas phase synthesis.
Using a special type of flame aerosol reactor, the researchers produced nanocomposites of noble metal-titanium dioxide. These were compared with titanium dioxide (TiO2) nanoparticles devoid of noble metal. Their photocatalytic activity was tested by degrading methyl orange dye solution.
Noble metals were found to trap or remove electrons from the TiO2 surface. This led to improved separation of electrons and holes enhancing photocatalytic activity of the nanocomposites. Platinum exhibited the highest potential to remove or trap electrons.
The authors of this work are from: Aerosol and Air Quality Research Laboratory, Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, USA, Center for Environmental Science and Engineering, Indian Institute of Technology, Mumbai, India.
- Tiwari, V. et al. One-step synthesis of noble metal–titanium dioxide nanocomposites in a flame aerosol reactor. Appl. Catal. A: Gen. 345, 241-246 (2008) | Article |