FTIR study of the oxidation of amorphous carbon by ozone at 300 K — Direct COOH formation Original Research Article

The reaction of O3 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 υ(C–O) mode is observed to form near 1190 cm−1, as well as a broad υ(CO–H) mode at 3450 cm−1, indicative of the O3-induced formation of associated COOH groups. The original surface contains both aromatic and aliphatic υ(C–H) mode absorbances, which are consumed at similar rates by the O3. 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.