EFFECT OF OXYGEN PRESSURE AND CARBON BURN-OFF ON PRODUCT RATIO OF CARBON-OXYGEN REACTION

The reaction of Graphon with O2 has been studied at 625°C in a static system, using initial O2 pressures between 25 and 750 mTorr. and samples pre-oxidized to varying degrees of burn-off between 0 and 20 per cent. The reaction temperature was low enough for secondary reactions to be neglected. A mass spectrometer was used to monitor the partial pressures of O2, CO and CO2. During a reaction, after a brief induction period corresponding to the formation of stable complex on the carbon surface, the incremental product ratio CO CO2 became constant. This product ratio increased with initial carbon burn-off and decreased with initial O2 pressure. Stable complex formation increased with initial carbon burn-off and initial oxygen pressure. It is suggested that for a particular burn-off the product ratio is a function of both the amount of stable complex on the surface and the relative extent to which CO and CO2-generating sites are deactivated by stable complex formation. © 1969.