Development of three way catalytic converter for automotive exhaust gas

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.


Thermal stability and SO2 resistance of Pd/Rh-perovskite based three-way catalyst wash-coated on cordierite monoliths
Bayram, Bilal; Önal, Işık; Külah, Görkem (2022-01-01)
The effect of hydrothermal aging and SO2 poisoning on the three-way catalytic performance of dispersed Pd/Rh-based and Pd/Rh perovskite-based catalysts were studied by using a dynamic activity test system that simulates redox fluctuations of gasoline engine exhaust conditions. Both catalysts were supported on ceria-zirconia-alumina and wash-coated on cordierite monoliths and were characterized by ICP-OES, BET, XRD, TEM-EDX, DRIFTS, and CO chemisorption. Their performance was very close when the catalysts we...
Experimental investigation of surface roughness effects on the flow boiling of R134a in microchannels
Jafari, Rahim; Okutucu Özyurt, Hanife Tuba; Ünver, Hakkı Özgür; Bayer, Özgür (2016-12-01)
This study experimentally investigates the effect of surface roughness on the hydrodynamic and thermal performance of microchannel evaporators. Three micro-evaporators of the same dimensions and different surface roughness have been fabricated by micro-WEDM. Each micro-evaporator consists of forty rectangular microchannels of 700 mu m height, 250 mu m width, and 19 mm length. A microscale vapor compression refrigeration cycle has been constructed to carry out the experiments. R134a is used as the refrigeran...
Modeling and sensitivity analysis of high temperature PEM fuel cells by using Comsol Multiphysics
Sezgin, Berna; Caglayan, Dilara Gulcin; DEVRİM, YILSER; Steenberg, Thomas; Eroğlu, İnci (2016-06-22)
The objective of this study is to observe the effect of the critical design parameters, velocities of inlet gases (hydrogen and air) and the conductivity of polymer membrane, on the performance of a high temperature PEM fuel cell. A consistent and systematic mathematical model is developed in order to study the effect of these parameters. The model is applied to an isothermal, steady state, three-dimensional PEM fuel cell in order to observe concentration profiles, current density profiles and polarization ...
Thermal degradation of polysiloxane and polyetherester containing benzoxazine moieties in the main chain
Bagherifam, Shahla; Kışkan, Barış; Aydogan, Binnur; Yagci, Yusuf; Hacaloğlu, Jale (2011-01-01)
In this study investigation of thermal characteristics of polysiloxane and polyetherester containing benzoxazine moieties in the main chain was performed via pyrolysis mass spectrometry. Pyrolysis mass spectrometry analyses revealed that the thermal stability and the extent of cross-linking enhanced when the benzoxazine moieties were separated by thermally more stable units such as siloxanes. However, when the siloxane chain units were long, possibility of polybenzoxazine growth decreased significantly and ...
Induction thermal plasma synthesis of Mg2Ni nanoparticles
Aktekin, Burak; ÇAKMAK, GÜLHAN; Öztürk, Tayfur (2014-06-15)
A study was carried out into possibility of thermal plasma synthesis of Mg2Ni nanoparticles. Both prealloyed powders and elemental powders were used as precursors in an inductively coupled thermal plasma incorporating two injection probes located axially in the reactor one from the top and the other from the bottom. The study has shown that the use of prealloyed Mg2Ni as precursor leads to its disintegration in the plasma condensing into separate phases and therefore was not suitable for the synthesis of Mg...
Citation Formats
B. Bayram, “Development of three way catalytic converter for automotive exhaust gas,” Ph.D. - Doctoral Program, Middle East Technical University, 2021.