Development of three way catalytic converter for automotive exhaust gas

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2021-7-9
Bayram, Bilal
In this study, a novel perovskite-based three-way catalyst (LaFe0.57Co0.37Pd0.06O3/Ce0.8Zr0.2O2/Al2O3) with high performance, thermal stability and SO2 poisoning resistance was developed. The performance of the developed catalyst was compared to a standard catalyst based on dispersed metal (Pd/Rh/ Ce0.8Zr0.2O2 / Al2O3). Performance evaluations were carried out in a dynamic activity test system that simulates redox fluctuations in the exhaust of gasoline engines. ICP-OES, BET surface area, X-ray diffraction, TEM-EDX spectroscopy, DRIFTS and CO chemisorption techniques were used for the characterization of catalysts. The performances of the catalysts before aging were obtained close to each other. After hydrothermal aging at 1273 K, perovskite-based catalyst was able to maintain its activity to a great extent. However, there was a serious activity loss in the standard catalyst, and NO and C3H8 conversions could not exceed 20% even at 600 oC. XRD revealed palladium substitution in the B site of the perovskite structure, which was seen as evidence of thermal stability. The growth of the Pd crystallite size from 3.4 nm to 28.1 nm was evaluated as evidence of the activity loss for standard catalyst. The CO chemisorption findings were also in parallel with the activity test, according to which the standard catalyst lost 85% and the perovskite-based catalyst lost only 30% CO uptake capacity.

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Citation Formats
B. Bayram, “Development of three way catalytic converter for automotive exhaust gas,” Ph.D. - Doctoral Program, Middle East Technical University, 2021.