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dc.contributor.authorRaj, Abhijeet
dc.contributor.authorYang, Seung Yeon
dc.contributor.authorCha, Dong Kyu
dc.contributor.authorTayouo Djinsu, Russell
dc.contributor.authorChung, Suk Ho
dc.date.accessioned2015-08-03T11:15:54Z
dc.date.available2015-08-03T11:15:54Z
dc.date.issued2013-09
dc.identifier.citationRaj, A., Yang, S. Y., Cha, D., Tayouo, R., & Chung, S. H. (2013). Structural effects on the oxidation of soot particles by O2: Experimental and theoretical study. Combustion and Flame, 160(9), 1812–1826. doi:10.1016/j.combustflame.2013.03.010
dc.identifier.issn00102180
dc.identifier.doi10.1016/j.combustflame.2013.03.010
dc.identifier.urihttp://hdl.handle.net/10754/562929
dc.description.abstractSoot particles are composed of polycyclic aromatic hydrocarbons (PAHs), which have either planar or curved structures. The oxidation behaviors of soot particles differ depending on their structures, arrangement of PAHs, and the type of surface functional groups. The oxidation rate of curved PAHs in soot is thought to be higher than that of planar ones. To understand the role that PAH structure plays in soot reactivity towards O2, experimental studies are conducted on two types of commercially produced soot, Printex-U and Fullerene soot, using high resolution transmission electron microscopy, electron energy loss spectroscopy, thermo-gravimetric analysis and elemental analysis. The relative concentrations of active sites, oxygenated functional groups, aliphatics and aromatics present in soots are evaluated. The activation energies for soot oxidation at different conversion levels are determined. The average activation energies of the two soots are found to differ by 26kJ/mol. To understand the reason for this difference, quantum calculations using density functional (B3LYP) and Hartree-Fock theories are conducted to study the reaction pathways of the oxidation by O2 of planar and curved PAHs using 4-pyrenyl and 1-corannulenyl as their model molecules, respectively. The energetically preferred channels for curved PAH oxidation differ from the planar one. The addition of O2 on a radical site of a six-membered ring to form a peroxyl radical is found to be barrierless for both the model PAHs. For peroxyl decomposition, three pathways are suggested, each of which involve the activation energies of 108, 170 and 121kJ/mol to form stable molecules in the case of planar PAH, and 94, 155 and 125kJ/mol in the case of curved PAH. During the oxidation of a five-membered ring, to form stable molecules, the activation energies of 90kJ/mol for the curved PAH and 169kJ/mol for the planar PAH relative to the energy of the peroxyl radical are required. The low activation barriers of preferred pathways for the oxidation of six and five-membered rings present on curved PAH (as compared to the planar one) explain and support its experimentally observed high reactivity. © 2013 The Combustion Institute..
dc.description.sponsorshipThis work was supported by Saudi Aramco through KAUST CCRC.
dc.publisherElsevier BV
dc.subjectDensity functional theory
dc.subjectKinetic mechanism
dc.subjectOxidation
dc.subjectPAH
dc.subjectSoot
dc.titleStructural effects on the oxidation of soot particles by O2: Experimental and theoretical study
dc.typeArticle
dc.contributor.departmentAdvanced Nanofabrication, Imaging and Characterization Core Lab
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Division
dc.contributor.departmentClean Combustion Research Center
dc.contributor.departmentCombustion and Laser Diagnostics Laboratory
dc.contributor.departmentCore Labs
dc.contributor.departmentImaging and Characterization Core Lab
dc.contributor.departmentMechanical Engineering Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)
dc.identifier.journalCombustion and Flame
dc.contributor.institutionDepartment of Chemical Engineering, The Petroleum Institute, Abu Dhabi, United Arab Emirates
kaust.personRaj, Abhijeet
kaust.personYang, Seung Yeon
kaust.personCha, Dong Kyu
kaust.personChung, Suk Ho
kaust.personTayouo Djinsu, Russell


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