Mechanistic impotance of intermediate N2 O + CO reaction in overall NO + CO reaction system

This paper investigates both theoretically and experimentally, the mechanistic importance of the N2O + CO reaction as an intermediate reaction step during the reduction of NO by CO occurring on noble metal exhaust catalysts. Quasilinearization of the non-linear NO + CO reaction system by identifying a critical kinetic parameter has revealed that the rate of the N2O + CO reaction as an intermediate reaction step in the overall NO + CO reaction system can be 2-to-3 orders of magnitude faster than the isolated N2O + CO reaction. Contrary to the traditional belief, this suggests that the formation of N2O and its subsequent reaction with CO can make a major contribution to the kinetics of the reduction of NO by CO in three-way catalytic converters. The validity of the theoretical results has been verified by both steady-state and isotopic transient experiments using microreactors containing conventional Rh/Al2O3 or Rh/CaO2 catalysts as well as the novel RH/CeO2-Gd2O3 catalysts developed recently in our laboratory