Modelling study of the temperature-programmed conversion curves of NO reduction by CO over supported Pt- and Rh-based catalysts

We have attempted to model the rate of NO transformation on a sintered Pt-R h/Al2O3 three-way catalyst (TWC) in various temperature and conversion cond itions close to the actual ones in TWCs. For this purpose a rate expression , previously established from kinetic measurements performed at a single te mperature of 300 degreesC, was used. The temperature dependency of the kine tic and thermodynamic parameters, using a non-linear optimisation, has been previously determined. Then, temperature-programmed experiments, performed in a fixed-bed flow reactor at atmospheric pressure under differential con ditions, have been modelled using such parameters. A similar procedure has been achieved for modelling the TP experiments on Rh/Al2O3. Both results ha ve been compared and discussed in the light of previous surface characteris ations.