KINETICS AND MECHANISMS OF THE CARBON-STEAM REACTION ON THE MONOLAYER AND MULTILAYER EDGES OF GRAPHITE

Turnover frequency rates, i. e. rates per active edge-carbon site, on both monolayer and multilayer edges were measured for the C plus H//2O reaction at 700, 800 and 900 degree C. Additional experimental results indicated that the 0. 5th order for H//2 was due to dissociative chemisorption of H//2. The turnover rates on multilayer edges were higher than the monolayer edges by approximately one order of magnitude. Theoretical values of the elementary rate constants compare reasonably well with experimental values. Atomic oxygen formed by dissociation of H//2O was responsible for vacancy formation. H or OH species were responsible when H//2 was present in the gas phase.