The reaction of hydroxyl radicals with carbon at 298 K

Abstract

The reaction of free OH radicals with graphite was studied in a flow system by mass spectrometry, the OH being produced by the reaction H + NO 2 → OH + NO. The OH radicals react rapidly at 298 K to produce approximately equal amounts of CO and CO 2. The collision efficiency (γ) for gasification of the carbon is>5 × 10 −3. OH radicals are much more reactive than free oxygen atoms towards graphite at 298 K. Carbon is an efficient heterogeneous catalyst for the reaction H + OH → H 2 O, and when free hydrogen atoms are present, this reaction is several times faster than the gasification of the carbon by OH. Carbon is also an efficient catalyst for the recombination of H atoms: 2H → H 2.