title: Visible-light photoresponse of gold nanoparticles supported on TiO2 : a combined photocatalytic, photoelectrochemical, and transient spectroscopy study.
abstract: In the context of gaining understanding on the origin of the visible-light photoresponse of TiO2 containing gold nanoparticles, the photocurrent spectra and photocatalytic H2 evolution of titania (P25) and Au-P25 were compared. Whereas no photocurrent was detected upon visible-light irradiation for either of the two photocatalysts, Au-P25 exhibited photocatalytic H2 evolution for wavelengths between 400 and 575 nm. This contradictory behavior under visible-light irradiation of Au-P25 was rationalized by transient absorption spectroscopy. It was suggested that photocatalytic H2 generation results from methanol quenching of the charge-separation state in each semiconductor nanoparticle, but the lack of photocurrent is due to the short lifetime of the charge separation, which makes interparticle charge migration for micrometric distances unlikely.
authors.affiliation: Instituto Universitario de Tecnología Química CSIC-UPV and Departamento de Química, Univ. Politécnica de Valencia, Av. De los Naranjos s/n, 46022 Valencia (Spain).
authors.forename: Herme G
authors.initials: HG
authors.lastname: Baldovi
authors.forename: Ferran
authors.initials: F
authors.lastname: Albarracin
authors.forename: Pedro
authors.initials: P
authors.lastname: Atienzar
authors.forename: Belen
authors.initials: B
authors.lastname: Ferrer
authors.forename: Mercedes
authors.initials: M
authors.lastname: Alvaro
authors.forename: Hermenegildo
authors.initials: H
authors.lastname: Garcia
keywords: gold; nanoparticles; photocatalysis; titanium dioxide; transient absorption spectroscopy