Abstract: A reverse-layered, catalyzed adsorber system for treating exhaust gas comprises a catalyst washcoat supported by a catalyst substrate, with an adsorption material disposed over at least a portion of the catalyst washcoat. During the treatment of the hydrocarbons from an internal combustion engine exhaust, the adsorption material layer adsorbs hydrocarbons from the exhaust gas. A built-in catalyst layer later catalyzes the conversion of the hydrocarbons released from the adsorption material when the adsorber system is hot.

Abstract: A method of reducing the amounts of nitrogen oxides and hydrocarbons in the exhaust gas from a small, gasoline-fueled utility engine operating fuel-rich, while not reducing the amount of carbon monoxide in said exhaust gas, comprising treatment of said exhaust gas by a catalyst consisting essentially of rhodium supported on an alumina-based washcoat applied to a substrate.

Abstract: The invention provides a catalyst which can convert methane, carbon monoxide, and nitrogen oxides in lean, stoichiometric, and rich air/fuel environments. Support (A) of the catalyst comprises an alumina support impregnated with Pd providing lean methane conversions and support (B) of the catalyst comprises ceria/lanthana/alumina impregnated with Pd providing stoichiometric methane conversion. Rhodium may be substituted for all or part of the Pd on an alumina support.

Abstract: The invention provides a catalyst which can convert methane, carbon monoxide, and nitrogen oxides in lean, stoichiometric, and rich air/fuel environments. Support (A) of the catalyst comprises an alumina support impregnated with Pd providing lean methane conversions and support (B) of the catalyst comprises ceria/lanthana/alumina impregnated with Pd providing stoichiometric methane conversion. Rhodium may be substituted for all or part of the Pd on an alumina support.

Abstract: A palladium three-way catalyst is supported on a unique ceria-lanthana-alumina support where the alumina content is lower than previously believed necessary to maintain catalyst activity. Preferably the ceria and lanthana constitute the major proportion of the support.

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.

Abstract: A three-way catalyst for use in treating automotive exhaust gases employs a delta alumina support which contains oxides of cerium plus barium and/or lanthanum, plus at least one Group VIII noble metal from the group consisting of platinum, palladium, rhodium, ruthenium and iridium.