AUTOMOBILE CATALYTIC CONVERTERS.

Abstract

Catalysts have been widely used to lower the emissions of carbon monoxide and hydrocarbons in the exhaust of automobiles in the United States since the introduction of 1975 models. These catalysts, contained in so-called catalytic converters in the exhaust system of automobiles, promote the oxidation of CO and HC to CO//2 and H//2O under net oxidizing conditions. NO//x emissions from gasoline engines have also been subject to catalytic control. Stringent federally mandated emission control requirements of 1 gram per mile (g mi** minus **1) for NO//x have led to the further application of three-way catalysts. This review emphasizes the state-of-the-art of catalytic control of automobile exhaust emissions, specifically three-way catalysts.