Exhaust gas catalyst and exhaust gas processing apparatus using same
AssigneeJohnson Matthey Japan Incorporated
InventorsJin Cho, Tomotaka Hirota, Kenji Tanikawa
Life of this patent
Estimating the term…
Abstract
An exhaust gas catalyst where the catalyst efficiency is improved by enhancing diffusion of the exhaust gas in a catalyst layer. An exhaust gas catalyst comprises at least a carrier and a plurality of layers formed on the carrier. At least one of the layers has pores therein, and at least one other layer has pores therein and contains, as catalyst components, a noble metal, alumina and a complex oxide mainly containing ceria, zirconia and one or more rare earth elements other than cerium.
Claims18
An exhaust gas catalyst comprising at least a support and multiple layers formed on the support, wherein
- at least one of the multiple layers has voids therein formed via a forming agent;
- and
- the at least one of the multiple layers having voids therein comprises, as catalytic components, a noble metal, alumina, and one or more composite oxides comprising, as main components, ceria, zirconia and one or more rare earth elements except for ceria, wherein the average diameter of the voids ranges from not less than 0.2 μm to not more than 500 μm and the one or more composite oxides has a specific surface area, after a heat treatment at 1000° C. for 2 hours, of not less than 40 m2/g.
An exhaust gas apparatus, comprising one or more exhaust gas catalysts disposed within the apparatus and downstream of an exhaust gas discharged from the engine, wherein the one or more exhaust gas catalysts comprises at least a support and multiple layers formed on the support, wherein
- at least one of the multiple layers has voids therein formed via a forming agent;
- and
- the at least one of the multiple layers having voids therein comprises, as catalytic components, a noble metal, alumina, and one or more composite oxides comprising, as main components, ceria, zirconia and one or more rare earth elements except for ceria, wherein the average diameter of the voids ranges from not less than 0.2 μm to not more than 500 μm and the one or more composite oxides has a specific surface area, after a heat treatment at 1000° C. for 2 hours, of not less than 40 m2/g.
An apparatus for treating hydrocarbons, carbon monoxide or nitrogen oxides in the exhaust gas, said apparatus comprising one or more exhaust gas catalysts for oxidizing or reducing the hydrocarbons, carbon monoxide or nitrogen oxides in the exhaust gas into carbon dioxide, water or nitrogen gas, wherein the one or more exhaust gas catalysts comprises at least a support and multiple layers formed on the support, wherein
- at least one of the multiple layers has voids therein formed via a forming agent;
- and
- the at least one of the multiple layers having voids therein comprises, as catalytic components, a noble metal, alumina, and one or more composite oxides comprising, as main components, ceria, zirconia and one or more rare earth elements except for ceria, wherein the average diameter of the voids ranges from not less than 0.2 μm to not more than 500 μm and the one or more composite oxides has a specific surface area, after a heat treatment at 1000° C. for 2 hours, of not less than 40 m2/g.
Dependencies are inferred from the claim text.