Monolithic Three-way Palladium Catalytic Converters for Automobile Exhaust Emission Control

Document Type: Full article

Abstract

This article presents the research results on production and performance of palladium-only catalytic converters. Monolith is used as the catalyst carrier and gamma alumina as the substrate. Dipping method is used for monolith washcoating. Palladium as the active metal is impregnated on gamma alumina using wet impregnation to produce catalyst samples. The effects of factors such as percent solids in slurry, milling time, calcination time and temperature, pH and existence of Al(NO3)3 on wash-coat characteristics were studied experimentally. SEM, XRD and BET tests were carried out on the samples. Catalyst performance was tested in an experimental reactor that was designed for this research. The results show that catalytic activity increases as calcination time increases, whereas it declines as calcination temperature increases. Furthermore, as the slurry pH decreases, the catalytic activity also decreases. It was observed that impregnation of Al(NO3)3 does not have any effect on catalytic activity.

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