Formation of Environmentally Persistent Free Radicals on α-Al2O3

Niveen W. Assaf, Mohammednoor Altarawneh, Ibukun Oluwoye, Marian Radny, Slawomir M. Lomnicki, Bogdan Z. Dlugogorski

Research output: Contribution to journalArticlepeer-review


Metal oxides exhibit catalytic activity for the formation of environmentally persistent free radicals (EPFRs). Here, we investigate, via first-principles calculations, the activity of alumina α-Al2O3(0001) surface toward formation of phenolic EPFRs, under conditions relevant to cooling down zones of combustion systems. We show that, molecular adsorption of phenol on α-Al2O3(0001) entails binding energies in the range of -202 kJ/mol to -127 kJ/mol. The dehydroxylated alumina catalyzes the conversion of phenol into its phenolate moiety with a modest activation energy of 48 kJ/mol. Kinetic rate parameters, established over the temperature range of 300 to 1000 K, confirm the formation of the phenolate as the preferred pathways for the adsorption of phenol on alumina surfaces, corroborating the role of particulate matter in the cooling down zone of combustion systems in the generation of EFPRs.

Original languageEnglish
Pages (from-to)11094-11102
Number of pages9
JournalEnvironmental Science and Technology
Issue number20
Early online date9 Sept 2016
Publication statusPublished - 18 Oct 2016
Externally publishedYes


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