High durability and exhuast catalyst with low hydrogen sulfide emissions

Abstract

This invention relates to a high durability catalyst for treating automotive exhaust gas which produces a minimal amount of hydrogen sulfide and is essentially free of cerium oxide and which comprises a support consisting substantially of delta alumina, an effective amount of a promoter consisting essentially of barium oxide and, optionally, lanthanum oxide, and, effective amounts of the noble metals palladium and rhodium deposited on the support. In an additional embodiment of the invention,m the support may contain delta alumina, and, optionally zirconia, and the catalyst may contain an overlayer containing delta or gamma alumina, and optionally, zirconia. Effective amounts of the noble metals palladium and rhodium may be deposited on the support and/or on the overlayer. In another aspect, the invention resides in a process for treating the exhaust gases from automotive engines to remove carbon monoxide, hydrocarbons, and nitrogen oxides, and to minimize the production of hydrogen sulfide.