title: Long-lived (minutes) photoinduced charge separation in a structured periodic mesoporous titania containing 2,4,6-triphenylpyrylium as guest.
abstract: 2,4,6-Triphenylpyrylium (TP(+)), an electron acceptor, has been included inside the channels of two ordered mesoporous titania (mpTiO(2)). MpTiO(2) contain anatase nanoparticles (3-5 nm) templated by cetyltrimethylammonium and differ by the presence or absence of silica domains as binders of the structure. UV irradiation of TP-mpTiO(2) gives rise to a strong EPR signal. This behaviour was not observed for related materials in which TP(+) was included inside the channels of MCM-41 or the cavities of zeolite Y. Also, transient spectroscopy shows remarkable differences between TP(+) included in mpTiO(2) (charge separation) and in porous silicates (triplet excited state). Based on EPR and laser flash spectroscopic evidence, the occurrence of photo-induced electron transfer from TiO(2) as the donor to TP(+) as the acceptor leading to a long-lived (minutes at room temperature) charge separated state is proposed.
authors.affiliation: Instituto de Tecnología Química CSIC-UPV, Universidad Politécnica de Valencia, Av. De los Naranjos s/n, 46022 Valencia, Spain.
authors.forename: Carmela
authors.initials: C
authors.lastname: Aprile
authors.forename: Luca
authors.initials: L
authors.lastname: Maretti
authors.forename: Mercedes
authors.initials: M
authors.lastname: Alvaro
authors.forename: J C
authors.initials: JC
authors.lastname: Scaiano
authors.forename: Hermenegildo
authors.initials: H
authors.lastname: Garcia