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Visible‐Light Photoresponse of Gold Nanoparticles Supported on TiO 2 : A Combined Photocatalytic, Photoelectrochemical, and Transient Spectroscopy Study
Author(s) -
Baldovi Herme G.,
Albarracin Ferran,
Atienzar Pedro,
Ferrer Belen,
Alvaro Mercedes,
Garcia Hermenegildo
Publication year - 2015
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402660
Subject(s) - photocatalysis , materials science , nanoparticle , visible spectrum , spectroscopy , transient (computer programming) , photochemistry , photoelectrochemistry , optoelectronics , ultrafast laser spectroscopy , colloidal gold , chemical engineering , nanotechnology , electrochemistry , chemistry , catalysis , electrode , biochemistry , physics , quantum mechanics , computer science , engineering , operating system
In the context of gaining understanding on the origin of the visible‐light photoresponse of TiO 2 containing gold nanoparticles, the photocurrent spectra and photocatalytic H 2 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 H 2 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 H 2 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.