Development of three way catalytic converters for elimination of hydrocarbons, carbon monoxide and nitric oxide in automotive exhaust

Download

index.pdf

Date

2014

Author

Civan, Aylin

Metadata

Show full item record

Item Usage Stats

298
views

121
downloads

In this study, catalytic performances of Three Way Catalysts (TWC) are investigated via Density Functional Theory (DFT) methods and catalytic activity tests in a dynamic test system simulating the exhaust conditions of automobiles. DFT techniques are implemented by Vienna Ab Initio Simulation Package (VASP) and effect of manganese doping in TWC compositions are evaluated with computations on manganese, palladium and rhodium substituted ceria-zirconia mixed oxide (CZO) surface models. Carbon monoxide oxidation mechanisms and energetics are investigated on the model surfaces. Oxygen Storage Capacity (OSC) of CZO is remarkably enhanced by the synergistic effect of Pd and Mn doping. Accordingly, relative energy profile of CO oxidation mechanism on Pd-Mn substituted surface is found to be energetically most favored. Such an efficient collaboration is not observed with Rh and Mn doped CZO. In the experimental studies, TWC catalysts with varying compositions of Pd, Mn and Rh are synthesized via impregnation and solution combustion methods. Powder catalysts are then mixed with gamma alumina and washcoated on laboratory scale cordierite monoliths. Catalytic activity tests of the monolithic catalysts are carried out in a dynamic activity test system. Online data are simultaneously collected by a Mass Spectrometer (MS) and a CO analyzer coupled to the test system. Performance of the catalysts are evaluated by means of light-off temperatures. Activity results of 28 tests are examined in terms of thermal aging and SO2 exposure. In compliance with the findings of the computational studies, catalytic performance is improved when Pd is coupled with Mn in catalyst compositions in both synthesis techniques.

Subject Keywords

Catalysts., Hydrocarbons., Carbon monoxide., Nitric oxide., Automobiles

URI

http://etd.lib.metu.edu.tr/upload/12617696/index.pdf
https://hdl.handle.net/11511/23842

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Removal of hydrocarbons, carbon monoxide and nitric oxides in automotive exhaust with three way catalytic converter Gerçeker, Duygu; Önal, Işık; Department of Chemical Engineering (2013) In this study, Three Way Catalysts (TWC) are investigated by using Density Functional Theory (DFT) methods and catalytic activity tests in the dynamic test system. Pd4 or Rh4 cluster adsorbed on ceria (CeO2) and ceria-zirconia (CZO) surfaces together with atomic palladium and rhodium substituted CeO2 and CZO surfaces are investigated for their catalytic activity towards carbon monoxide oxidation and nitric oxide reduction. Relative energy profiles for reaction mechanisms are obtained and activation barriers...
Quantum mechanical investigation of CO oxidation conducted on automotive exhaust emission catalysts containing LA and PD/LA on Ceria-Zirconia Kaya, Yasemin; Önal, Işık; Department of Chemical Engineering (2016) In this study, Three Way Catalyst (TWC) is investigated via Density Functional Theory (DFT) methods. DFT techniques are implemented by Vienna Ab Initio Simulation Package (VASP). Atomic lanthanum substituted and both palladium and lanthanum substituted CZO (110) surfaces are investigated for their catalytic activity in terms of carbon monoxide oxidation. Relative energy profiles for CO reaction mechanisms on these surfaces are obtained and activation barriers of reaction steps are analyzed by using CI-NEB m...
Experimental investigation of CO tolerance in high temperature PEM fuel cells DEVRİM, YILSER; Albostan, Ayhan; Devrim, Huseyin (Elsevier BV, 2018-10-04) In the present work, the effect of operating a high temperature proton exchange membrane fuel cell (HT-PEMFC) with different reactant gases has been investigated throughout performance tests. Also, the effects of temperature on the performance of a HT-PEMFC were analyzed at varying temperatures, ranging from 140 degrees C to 200 degrees C. Increasing the operating temperature of the cell increases the performance of the HT-PEMFC. The optimum operating temperature was determined to be 160 degrees C due to th...
Computational fluid dynamics simulation of the combustion process, emission formation and the flow field in an in-direct injection diesel engine Barzegar, Ramin; Shafee, Sina; Khalilarya, Shahram (National Library of Serbia, 2013) In the present paper, the combustion process and emission formation in the Lister 8.1 in-direct injection diesel engine have been investigated using a computational fluid dynamics code. The utilized model includes detailed spray atomization, mixture formation and distribution model which enable modeling the combustion process in spray/wall and spray/swirl interactions along with flow configurations. The analysis considers both part load and full load states. The global properties are presented separately re...
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...

Citation Formats

A. Civan, “Development of three way catalytic converters for elimination of hydrocarbons, carbon monoxide and nitric oxide in automotive exhaust,” M.S. - Master of Science, Middle East Technical University, 2014.