Environmental green chemistry applications of nanoporous carbons

摘要

Influence of surface properties of nanoporous carbons on activity and selectivity during the photooxidation of 4-chlorophenol on UV-irradiated TiO₂ was performed. Characterization by infrared spectroscopy, X-ray photoelectronic spectroscopy and X-ray absorption near edge structure spectroscopy confirm the presence of a contact interface between both solids and suggest the coordination of some functional organic groups of the carbon surface, mainly ethers and carboxylic acids, to metallic centre Ti+4 in TiO₂. Changes in surface pH of carbons from basic to neutral or acid remarkably increase the production of 4-chlorocathecol by a factor of 22 on TiO₂–Carbon in comparison of TiO₂ alone. A scheme of interaction between TiO₂ and carbon is proposed to the increased photoactivity of TiO₂ and a reaction mechanism for the different intermediate products detected is also proposed. Results showed that TiO₂–Carbon can be used as an alternative photocatalyst for environmental green chemistry and selective organic synthesis applications.