FTIR study of the oxidation of amorphous carbon by ozone at 300 K - Direct COOH formation

The reaction of O-3 with activated carbon has been investigated with transmission FTIR spectroscopy. A wide range of carbonyl species are observed to form with stretching mode frequencies ranging up to 1900 cm(-1), but individual carbonyl species cannot be resolved. A nu (C-O) mode is observed to form near 1190 cm(-1), as well as a broad V(CO-H) mode at 3450 cm(-1), indicative of the O-3-induced formation of associated COOH groups. The original surface contains both aromatic and aliphatic nu (C-H) mode absorbances, which are consumed at similar rates by the O-3. A mechanism is proposed for COOH formation through decomposition of an ozonide, where the hydrogen originates from C-H bonds initially present on the carbon surface. (C) 2001 Elsevier Science Ltd. All rights reserved.