Automotive exhaust emission control using doped Perovskite based catalysts (A literature review)

Carbon monoxide, oxides of nitrogen, unburnt hydrocarbons and particulate matter are the principal air quality pollutant emission from automobiles. Number of automobiles are rocketed in recent years all over the world. Carbon monoxide it reduces the blood oxygen-carrying capacity which can reduce the availability of oxygen to key organs. Extreme level of exposure can be fatal. Maximum 8 hours average CO level allowed by WHO is 10mg/m3 Thus, it is very necessary to control exhaust emission from automotive source for environment. Catalytic converters are used for this purpose which converts carbon monoxide into less harmful carbon dioxide. Catalytic converters are not only useful for automobile but also in forklifts , mining equipments, generator sets, locomotives, motor cycles, airplanes etc. Three way oxidation- reduction catalytic converters are used in gasoline- powered vehicle for strict vehicle emission regulations. Research has been carried out and still going on for development of more economical and efficient catalyst. Originally very expensive metals Pt and Rh were used. Perovskites are one of these development but low surface area is its limitation. To overcome this limitation doped perovskite is the solution which reduces 70% decrease in precious metal usage. To develop doped perovskites using different material and different method to make catalyst more economical and efficient will be goal of the research work.