An empirical model is fitted to the performance of NO reduction by CO gas on an alumina fibrous catalyst support media The model is highly non-linear and contains 13 fitted parameters. To fit the reaction kinetic parameters in the model to the experimental results, a genetic algorithm was applied to search for the best fit parameter values. The fitted model and experimental results for Pd. Pt and Rh catalysts are in good agreement. The effects of NO decomposition by varying fiber diameter, media depth, and catalyst particle size on rhodium catalyst can be calculated from the model The model results show the temperature of complete NO decomposition decreases with greater media depth, higher fractional area of coverage by the catalyst particles, and with smaller catalyst particle size. (C) 2009 Elsevier Ltd. All rights reserved.