Development and Performance Evaluation of a Non-Noble Metal Based Catalytic Converter for Gasoline Engine

Abstract

With increase in urbanization and consequent growth in vehicular fleets, resulting air pollution is becoming serious problem for urban environment. One of the technological options to control vehicular emissions is catalytic converters. Conventionally, precious metals e.g. Pt, Pd and Rh, collectively named as Platinum group metals (PGMs) have been used as a catalyst in catalytic converters. However, increasing prices of PGMs and their adverse effects on human health and environment, necessitate the investigation of potential low priced alternatives such as Co3O4/TiO2. Co3O4 supported over TiO2 has been previously investigated for low temperature oxidation of CO in controlled laboratory environment, however, it has yet to be tested under real vehicular engine exhaust conditions. Here we report catalytic converter based on Co3O4/TiO2 as catalyst with stainless steel wire mesh as a substrate. Catalyst was prepared by wet impregnation (WI) as well as incipient wetness impregnation (IWI) methods. Catalyst was deposited on wire mesh via dipping technique and tested for oxidation of CO and HC present in the tailpipe emissions of motorcycle in idle condition at different rpm ranging from low to high. The conversion efficiencies were superior in catalysts prepared with IWI method as compared to WI method. Then IWI catalyst was taken for testing in real driving conditions ranging from 15 km/h to 40 km/h on a 2 km patch of a road. Reduced efficiency of catalyst was observed in real driving conditions due to high load of pollutants in case of HC and in case of CO reduced efficiency was observed due to presence of NOx