Isotopic transient study of methanol decomposition over noble metal/ceria catalysts

Methanol decomposition reaction was studied over combustion-synthesized noble metal (Pt, Pd, Rh)/ceria catalysts using the steady-state isotopic transient kinetic analysis (SSITKA) method. The 13C-containing reactants and products were monitored following a 12CH3OH/Ar/He → 13CH3OH/He switch. Average life-time and concentration of adsorbed intermediate species which lead to CO, and overall reaction rate at 220 °C, were determined. Significant amounts of active intermediate species were formed on the ceria support or/and metal-ceria interface. A clear concave shape of the curve of the semilogarithmic plot of the molar fraction of CO versus time was indicative of a parallel mechanism followed for its formation.