Research Scholar

Burcu Mirkelamoglu, Department of Chemical and Biomolecular Engineering
Umit S. Ozkan, Faculty advisor
Meimei Liu, Co-Researcher
Samuel D. Lentz, Co-Researcher

Biography

Burcu Mirkelamoglu joined  The Ohio State University, Department of Chemical and Biomolecular Engineering in 2006 as a post-doctoral research associate. Dr. Mirkelamoglu earned her Ph.D. degree in chemical engineering from Middle East Technical University, Turkey in 2006 where, she worked on low temperature catalytic oxidation of carbon monoxide in hydrogen rich streams for fuel-cell applications. Her current research interests include catalytic elimination of NOx species from lean burn engine exhausts and application of novel oxidizing agents for oxidative dehydrogenation of lower alkanes.

About the Research

To meet the increasingly stringent emissions regulations, significant research efforts are being devoted to the development of exhaust gas aftertreatment systems which would make use of the unburned hydrocarbons in the exhaust stream for the reduction of NOx species under lean burn conditions and would minimize or eliminate the fuel penalty. Methane has attracted special attention due to its low cost and availability however, the use of methane as a reducing agent poses significant challenges since, methane combustion with oxygen is more favorable than NOx reduction under lean conditions. Current research focuses on the development of highly active and selective supported metal-oxide catalysts for a dual-stage mechanism where, NO in the exhaust stream will be oxidized to NO₂ in the first stage and, NO₂ will be reduced to N₂ with hydrocarbons as the reducing agents in the next stage. The rationale for the approach is that NO₂ is a stronger oxidizing agent than NO and therefore, is better able to compete with O₂ for the use of the reducing agent giving higher N₂ yields. Furthermore, the presence of the oxidation catalyst would replenish NO₂ that has been partially reduced to NO through a competitive reaction during direct NO₂ reduction. The dual catalyst system contains a cobalt-based oxidation catalyst for oxidizing NO to NO₂ in the first stage and, a noble metal-based reduction catalyst to reduce NO₂ to N₂. Catalysts were tested in laboratory scale reactors under simulated lean exhaust conditions and characterized using an array of spectroscopic techniques for the development of a fundamental understanding of the catalytic reactions that would enable the development of highly active and selective catalyst formulations. Test results on the dual-catalyst system show that the system is not only capable of achieving high NOx conversion and N₂ yields without the injection of additional hydrocarbon reducing agents thus eliminating fuel penalties but also, it has the potential to replace the current oxidation catalysts used in exhaust aftertreatment systems since the system is very active for the elimination of CO, C₃H₈, C₂H₆ and CH₄. Another important feature of the dual-stage approach is that it can be retrofitted to lean burn natural gas engines without engine modification and implementation of additional control mechanisms.