초록 ▼

Oxidation catalyst compositions for treating diesel exhaust include ceria and, optionally, alumina, each having a surface area of at least about 10 m.sup.2 /g, and a zeolite, e.g., Beta zeolite. Optionally, platinum may be included in the catalytic material, preferably in amounts which are sufficien

Oxidation catalyst compositions for treating diesel exhaust include ceria and, optionally, alumina, each having a surface area of at least about 10 m.sup.2 /g, and a zeolite, e.g., Beta zeolite. Optionally, platinum may be included in the catalytic material, preferably in amounts which are sufficient to promote some gas-phase oxidation of carbon monoxide ("CO") and hydrocarbons ("HC") but which are limited to preclude excessive oxidation of SO.sub.2 to SO.sub.3. Alternatively, palladium in any desired amount may be included in the catalytic material. The zeolite is optionally doped, e.g., ion-exchanged, with one or more of hydrogen, a platinum group metal or other catalytic metals. The catalyst compositions may be used in a method to treat diesel engine exhaust by contacting the hot exhaust with the catalyst composition to promote the oxidation of gas-phase CO and HC and of the volatile organic fraction component of particulates in the exhaust.

대표청구항 ▼

[ What is claimed is:] [1.]1. A catalyst composition for treating a diesel engine exhaust stream containing gaseous hydrocarbons and a volatile organic fraction comprises a refractory carrier on which is disposed a coating of a catalytic material comprising: bulk ceria having a BET surface area of a

[ What is claimed is:] [1.]1. A catalyst composition for treating a diesel engine exhaust stream containing gaseous hydrocarbons and a volatile organic fraction comprises a refractory carrier on which is disposed a coating of a catalytic material comprising: bulk ceria having a BET surface area of at least about 10 m.sup.2 /g, iron-doped Beta zeolite and a catalytic metal selected from the group consisting of platinum and palladium.