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–Rh/Al2O3 three-way catalyst (TWC) in various temperature and conversion conditions close to the actual ones in TWCs. For this purpose a rate expression, previously established from kinetic measurements performed at a single temperature of 300°C, was used. The temperature dependency of the kinetic 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 conditions, have been modelled using such parameters. A similar procedure has been achieved for modelling the TP experiments on Rh/Al2O3. Both results have been compared and discussed in the light of previous surface characterisations.