Nippon Shokubai Co., Ltd.

Other

Satoshi Inui

Masao Hori

Kazuo Tsuchitani

Koichi Saito

Makoto Horiuchi

A catalyst for the purification of an exhaust gas emitting from a lean burn engine using gasoline as a fuel thereof and a method for the purification are provided. The catalyst has deposited on an inert carrier a mixture of a catalytically active component comprising palladium, an oxide of at least one alkali metal selected from the group consisting of potassium, sodium, rubidium, and cesium, and an oxide of at least one iron family metal selected from the group consisting of cobalt, nickel, and iron with a refractory inorganic oxide. This catalyst is used either alone or in combination with an oxidizing catalyst or a three-way catalyst for the purification of the exhaust gas from the lean burn engine using gasoline as a fuel thereof.

Catalyst for purifying exhaust gas from lean burn engine and method for purification

The removal of nitrogen oxides from an exhaust gas is accomplished by a method which comprises causing the exhaust gas in an oxidizing atmosphere to contact a catalyst comprising a refractory inorganic oxide and catalytically active components, the components comprising 0.1 to 30 g per liter of the catalyst of at least one noble metal selected from the group consisting of Pt, Pd, Rh, and Ru or a compound of the noble metal and 1 to 80 g per liter of the catalyst of at least one metal selected from the group consisting of Li, K, Na, Rb, Ce, Be, Mg, Ca, St, and Ba or a compound of the metal, thereby inducing the catalyst to adsorb thereon the nitrogen oxides in the exhaust gas and, subsequently introducing a reducing substance intermittently into the exhaust gas thereby purifying the exhaust gas by reducing the nitrogen oxides adsorbed on the catalyst.

Method for removal of nitrogen oxides from exhaust gas

A catalyst for purifying exhaust gas from Diesel engines, having a catalyst component-carrying layer made of a refractory three-dimensional structure having carried thereon a catalyst component containing (a) a refractory inorganic oxide, (b) at least one noble metal selected from palladium and platinum, and (c) rhodium, wherein the rhodium is contained only in an upper layer portion of the catalyst component-carrying layer corresponding to no more than 80% in thickness of the catalyst component-carrying layer.

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Hyogo, Japan

Satoshi Inui