title: Mechanistic Studies of TiO2Photocatalysis and Fenton Degradation of Hydrophobic Aromatic Pollutants in Water.
abstract: HO-adduct radicals have been investigated and confirmed as the common initial intermediates in TiO2photocatalysis and Fenton degradations of water-insoluble aromatics. However, the evolution of HO-adduct radicals to phenols has not been completely clarified. When 4-d-toluene and p-xylene were degraded by TiO2photocatalysis and Fenton reactions, respectively, a portion of the 4-deuterium or 4-CH3group (18-100 %) at the attacked ipso position shifted to the adjacent position of the ring in the formed phenols (NIH shift; NIH is short for the National Institutes of Health, to honor the place where this phenomenon was first discovered). The results, combined with the observation of a key dienyl cationic intermediate by in situ attenuated total reflectance FTIR spectroscopy, indicate that, for the evolution of HO-adduct radicals, a mixed mechanism of both the carbocation intermediate pathway and O2-capturing pathway occurs in both aqueous TiO2photocatalysis and aqueous Fenton reactions.
authors.affiliation: Key Laboratory of Photochemistry, National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China.|University of Chinese Academy of Sciences, Beijing, 100049, P.R. China.
authors.forename: Yuanzheng
authors.initials: Y
authors.lastname: Gong
authors.affiliation: Key Laboratory of Photochemistry, National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China.|University of Chinese Academy of Sciences, Beijing, 100049, P.R. China.
authors.forename: Chun
authors.initials: C
authors.lastname: Yang
authors.affiliation: Key Laboratory of Photochemistry, National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China.|University of Chinese Academy of Sciences, Beijing, 100049, P.R. China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Ji
authors.affiliation: Key Laboratory of Photochemistry, National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China.|University of Chinese Academy of Sciences, Beijing, 100049, P.R. China.
authors.forename: Chuncheng
authors.initials: C
authors.lastname: Chen
authors.affiliation: Key Laboratory of Photochemistry, National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China.|University of Chinese Academy of Sciences, Beijing, 100049, P.R. China.
authors.forename: Wanhong
authors.initials: W
authors.lastname: Ma
authors.affiliation: Key Laboratory of Photochemistry, National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China.|University of Chinese Academy of Sciences, Beijing, 100049, P.R. China.
authors.forename: Jincai
authors.initials: J
authors.lastname: Zhao
keywords: NIH shift; hydroxylation of aromatics; photochemistry; reaction mechanisms; water chemistry