ABSTRACT
Automotive exhaust catalysts fall into the large family of total oxidation catalysts. As is true for the entire family of catalysts, there are many physical forms and many chemical compositions, each of which would be most effective under specific conditions. Some catalysts will be supported on granular supports, others on spherical supports, whereas others will be coated onto so-called honeycomb structures. In abatement processes the catalysts are frequently subjected to much more severe and less carefully controlled conditions than apply to a catalyst used in industrial processes. If there is abrasion of the catalyst, then the precious metals are most easily removed when the catalytic material is confined to the surface. If the catalyst has been deactivated by carbonaceous deposition, it can generally be regenerated by a careful oxidation to remove the carbonaceous material that is acting as a physical poison. There are several procedures that involve fusion of the spent catalyst.
