Modeling of CO Oxidation by Diffusion of Oxygen Atoms in Ceria-Zirconia Particulates in a Three-Way Catalyst Particle Membrane Filter

In order to design a microporous membrane filter comprising Three-way Catalyst (TWC) particles with a size distribution of 1 to 2 microns, isothermal CO oxidation experiments and numerical simulations were conducted to investigate the transport of oxygen atoms within primary Ceria-Zirconia (CZ) particulates. These spherical TWC particles were fabricated through the agglomeration of primary CZ and alumina particulates, incorporating Pd and Rh catalysts. By comparing experimental CO2 emissions with simulation results over time, a temperature-dependent diffusion coefficient was determined. The simulation results reveal that the effective distance of oxygen atom transport within CZ particulates, heterogeneously distributed in the spherical TWC particle, is limited to approximately 100 nm from the surface of agglomerated spherical TWC particles within a temperature range of 175 to 225°C.