Abstract: A method of making an ozone decomposition catalyst comprising an amorphous metal oxide consisting of manganese and, optionally, one or more of zirconium, silicon, titanium and aluminium, on a particulate support material, comprises the steps of preparing a mixture comprising an aqueous manganese salt and the support material and co-precipitating the metal oxide onto the support material.

Abstract: A three-way catalyst (TWC) composition comprises a manganese-containing oxygen storage component (OSC) and at least one optionally doped alumina wherein where the at least one alumina is gamma-alumina it is doped with at least one of a rare earth metal, silicon, germanium, phosphorus, arsenic, calcium, strontium or barium.

Abstract: New three-way catalysts for vehicles contain, as an oxygen storage component, mixed oxide MnZr. These components are less expensive than state-of-the-art ceria/zirconia, and generally offer improved capacity even after exposure to high temperatures.

Abstract: A process for the improved conversion of NO.sub.x in the exhaust gases from a light diesel engine using lean NO.sub.x catalyst converter in the exhaust system. The process is characterized in that unburned hydrocarbons are adsorbed into an adsorbent in the catalytic converter at temperatures below 190.degree. C. during cooler parts of the operating cycle, and are desorbed in the temperature range of 198.degree. to 200.degree. C. during hotter parts of the operating cycle. The desorbed hydrocarbons are combined with unburned hydrocarbons in the exhaust to form a composition stream having a higher amount of hydrocarbons than either constituent stream which are then oxidized at the same time as at least a portion of the NO.sub.x is catalytically reduced to form N.sub.2.