title: Role of water and carbonates in photocatalytic transformation of CO2 to CH4 on titania.
abstract: Using the electron paramagnetic resonance technique, we have elucidated the multiple roles of water and carbonates in the overall photocatalytic reduction of carbon dioxide to methane over titania nanoparticles. The formation of H atoms (reduction product) and (•)OH radicals (oxidation product) from water, and CO(3)(-) radical anions (oxidation product) from carbonates, was detected in CO(2)-saturated titania aqueous dispersion under UV illumination. Additionally, methoxyl, (•)OCH(3), and methyl, (•)CH(3), radicals were identified as reaction intermediates. The two-electron, one-proton reaction proposed as an initial step in the reduction of CO(2) on the surface of TiO(2) is supported by the results of first-principles calculations.
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States. dimitrijevic@anl.gov
authors.forename: Nada M
authors.initials: NM
authors.lastname: Dimitrijevic
authors.forename: Baiju K
authors.initials: BK
authors.lastname: Vijayan
authors.forename: Oleg G
authors.initials: OG
authors.lastname: Poluektov
authors.forename: Tijana
authors.initials: T
authors.lastname: Rajh
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Gray
authors.forename: Haiying
authors.initials: H
authors.lastname: He
authors.forename: Peter
authors.initials: P
authors.lastname: Zapol