DIFFUSIONAL EFFECTS AND INTRINSIC KINETICS FOR NO REDUCTION BY CO OVER PT-RH GAMMA-AL2O3 MONOLITHIC CATALYSTS

Experimental kinetic data have been obtained for the CO-NO reaction system over laboratory made platina-rhodium monolithic catalysts with different thicknesses of catalytic active substrate on a monolithic ceramic support. A synthetic gas mixture which consisted of CO, NO, and N2 was the feed of an integral tubular reactor between 200 and 350-degrees-C. A first-order kinetic rate expression with respect to NO concentration, which includes an inhibition term of second order, was found to fit the experimental data via a model which also accounts for internal transport resistances. The reaction rate constants, the activation energy of the reaction, the enthalpy of the adsorption process, and the effective diffusivity of NO were estimated. The obtained kinetic and diffusional data can be used in the design of a catalytic converter with improved efficiency.