Title: EPFR Formation from Phenol adsorption on Al2O3 and TiO2: EPR and EELS studies.
Authors: Patterson, Matthew C; Keilbart, Nathan D; Kiruri, Lucy W; Thibodeaux, Chad A; Lomnicki, Slawo; Kurtz, Richard L; Poliakoff, E D; Dellinger, Barry; Sprunger, Phillip T
Published In Chem Phys, (2013 Aug 30)
Abstract: We have examined the formation of environmentally persistent free radicals (EPFRs) from phenol over alumina and titania using both powder and single-crystal samples. Electron paramagnetic resonance (EPR) studies of phenol adsorbed on metal oxide powders indicates radical formation on both titania and alumina, with both oxides forming one faster-decaying species (lifetime on the order of 50-100 hours) and one slower-decayng species (lifetimes on the order of 1000 hours or more). Electron energy loss spectroscopy (EELS) measurements comparing physisorbed phenol on single-crystal TiO2(110) to phenoxyl radicals on the same substrate indicate distinct changes in the π-π* transitions from phenol after radical formation. The identical shifts are observed from EELS studies of phenoxyl radicals on ultrathin alumina grown on NiAl(110), indicating that this shift in the π-π* transition may be taken as a general hallmark of phenoxyl radical formation.
PubMed ID: 24443627
MeSH Terms: No MeSH terms associated with this publication