title: Oxidation of Graphene-Edge Six- and Five-Member Rings by Molecular Oxygen.
abstract: To gain qualitative and quantitative understanding of oxidation processes of large polycyclic aromatics, soot particles, and graphene edges, a theoretical study is reported for the pyrenyl-O2 reaction system. First, possible reaction pathways and their energetics were investigated using high-level ab initio calculations. The results were utilized in RRKM-master equation calculations of rate coefficients and relative product yields at temperatures and pressures relevant to combustion. Finally, the deduced oxidation mechanisms of six- and five-member rings and the computed rate coefficients were employed in kinetic Monte Carlo simulations of oxidation of a graphene "molecule" evolving in flame-like environments. Among the major findings from the latter simulations are the following: The oxidation system exhibits two basic pathways, thermal decomposition and regeneration of oxyradicals. Their competition is temperature-dependent, with the former dominating at higher and the latter at lower temperatures. The overall oxidation of the graphene substrate is computed to be time-dependent, with the initial rates consistent with the known experimental data.
authors.affiliation: ‡Department of Mechanical Engineering, University of California at Berkeley, Berkeley, California 94720-1740, United States.
authors.forename: Ravi I
authors.initials: RI
authors.lastname: Singh
authors.affiliation: †Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Mebel
authors.affiliation: ‡Department of Mechanical Engineering, University of California at Berkeley, Berkeley, California 94720-1740, United States.|§Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Frenklach