In Situ Determination of Surface Carbon Species Formed on Rh/Al2O3 During CO/H2 Reaction by using Various Transient and Isotopic Methods

Abstract

The evolution of surface species formed during the CO/H2 reaction at 220°C on a 1wt% Rh/Al2O3 catalyst was studied by transient methods using both mass spectrometry and FTIR. There is a very small amount of active carbon, Cα (θCα <0.05) and a large amount of surface CO (θCO=0.95). Also present on the Rh surface are a hydrogenated carbon and an inactive carbon, Cβ, species which do not exchange with gaseous or surface 13CO. The amount of these two species grows with time on stream. The kinetics of isothermal hydrogenation of carbon species formed after CO/H2 reaction depends on the Rh particle size. © 1993, Elsevier B.V. All rights reserved.