Synthesis of Perovskites Based Catalyst (Reactive Grinding Ball Milling) and its Application in Auto Exhaust Emission Control

Abstract

The automotive exhaust gas that exits from the engine contains poisonous components such as carbon monoxide, unreacted hydrocarbon and oxides of nitrogen. The automobile exhaust gases which can cause acid rain, photochemical smog, etc. So purification of automotive exhaust gas is required.These harmful components convert to inert gases such as carbon dioxide, water vapour, nitrogen and oxygen in catalytic converter before the exhaust gas emitted to the atmosphere. Catalyst like noble metals in catalytic converter can reduce the exhaust gas emission. Due to their high cost, volatization and sintering at high temperature, it is not beneficial for reducing exhaust emission. Perovskite type oxides, general formula ABO3 are the promising alternatives. They have a low cost, high thermal stability and physico-chemical properties. The major traditional drawback of perovskites is the low specific surface area (usually several m2/g) due to their preparation which involves high temperature (often as high as 800 ºC) to ensure the formation of the crystalline phase. This suppresses their activity and to some degree limits their application. A new preparation method called reactive grinding is developed for the synthesis of perovskites at room temperature via high-energy ball milling which results in a relatively high surface area that over come limitations of conventional methods for preparation of perovskites. Phase analysis and Crystallite size, specific surface area were investigated by XRD, N2 adsorption– desorption measurements (BET) respectively. The project is to illustrate the technology for abatement of exhaust emissions by analysis the current understanding of TWCs, the specific role of the various components, the achievements and the limitations. It also discusses Reactive Grinding ball mill, Perovskite, occurrence, their characterization, usage of perovskite in automobiles, advantages over conventional catalyst.