초록 ▼

An automotive exhaust catalyst includes a support, which is less likely to adsorb SO.sub.x contained in exhaust gases thereon, an NO.sub.x storage compound loaded on the support, and a noble metal element loaded on the support. The support is an alumina support with a Ti--Zr composite oxide loaded t

An automotive exhaust catalyst includes a support, which is less likely to adsorb SO.sub.x contained in exhaust gases thereon, an NO.sub.x storage compound loaded on the support, and a noble metal element loaded on the support. The support is an alumina support with a Ti--Zr composite oxide loaded thereon, or is formed of a Ti--Zr or Ti--Zr--Y composite oxide. The composite oxide inhibits the NO.sub.x storage compound, which is selected from alkali metals, alkaline-earth metals and rare-earth elements, from being poisoned by sulfur, and enhances the thermal resistance of the support. Thus, the automotive exhaust catalyst can effectively purify NO.sub.x contained in lean-side exhaust gases, even after it is subjected to a thermal durability test.

대표청구항 ▼

[ What is claimed is:] [1.] A process for purifying carbon monoxide, hydrocarbons and nitrogen oxides at the stoichiometric point or in exhaust gases in oxygen-rich atmosphere, thereby purifying the exhaust gases, the process comprising the step of:bringing exhaust gases at stoichiometric point or i

[ What is claimed is:] [1.] A process for purifying carbon monoxide, hydrocarbons and nitrogen oxides at the stoichiometric point or in exhaust gases in oxygen-rich atmosphere, thereby purifying the exhaust gases, the process comprising the step of:bringing exhaust gases at stoichiometric point or in oxygen-rich atmosphere, whose oxygen concentration is more than required for oxidizing the components to be oxidized therein, into contact with a catalyst:the catalyst comprising:an alumina support;a Ti--Zr composite oxide loaded on said alumina support;at least one NO.sub.x storage compound selected from the group consisting of alkali metals and alkaline-earth metals loaded on said alumina support; anda noble metal element loaded on said alumina support,whereby said nitrogen oxides in said exhaust gases are adsorbed to said NO.sub.x storage compound on said alumina support under an oxygen-rich atmosphere in which oxygen concentration is above the stoichiometric point that is required for oxidizing components to be oxidized in said exhaust gases, and said adsorbed nitrogen oxides are released and purified by a reaction with said hydrocarbons and carbon monoxide in said exhaust gases under a stoichiometric atmosphere or a reduction atmosphere in which oxygen concentration is below the stoichiometric point, andwhereby said Ti--Zr composite oxide inhibits said NO.sub.x storage compound from reacting with sulfur oxides contained in said exhaust gases to form sulfates and sulfites.