Abstract: Fine metal particles each comprising a magnetic metal core particle and two or more coating layers, the outermost layer among the two or more coating layers containing an oxide of silicon and aluminum at an Al/Si atomic ratio of 0.01-0.2, and a method for producing fine metal particles comprising the steps of coating each primary particle comprising a magnetic metal core particle and a first coating layer with a mixture of silicon alkoxide and aluminum alkoxide, and then hydrolyzing the silicon alkoxide and the aluminum alkoxide, thereby forming a second coating layer comprising an oxide of silicon and aluminum at an Al/Si atomic ratio of 0.01-0.2.

Abstract: A catalyst for purifying an exhaust gas for simultaneously removing carbon monoxide, hydrocarbons and nitrogen oxides contained in the exhaust gas under an oxygen rich atmosphere, comprising a carrier composed of a porous material, and barium oxide, lanthanum oxide and platinum supported on the carrier, and a method for purifying an exhaust gas by bringing the exhaust gas under an oxygen rich atmosphere into contact with the above-mentioned catalyst.