The CO H2 reaction on Rh Al2O3. I. Steady-state and transient kinetics

Abstract

Various hydrogen titrations yield the surface composition of Rh Al2O3 during the CO H2 reaction at temperatures in the range 180-260 °C. There is a very small amount of active carbon Ca, 0.02-0.06 monolayer, and 0.70-0.98 monolayer of CO on the metal surface. The coverage of H is low. Also present are inactive carbon Cβ on the metal and formate species on the support. The surface coverages are consistent with the observed steady-state kinetics, which result in methane as the predominant product. Although the rate-limiting step may be the dissociation of surface CO, it is found that the reaction sequence passes through a small coverage of highly active surface carbon Cα. © 1989.