title: Efficient photoinduced conversion of an azo dye on hexachloroplatinate(IV)-modified TiO2 surfaces under visible light irradiation-A photosensitization pathway.
abstract: The titanium dioxide photocatalyst is employed to examine the influence of chemisorbed hexachloroplatinate(IV) anions (PtCl(6) (2-)) on the surface of P-25 TiO(2) particles on the photoinduced conversion of the azo dye Ethyl Orange (EO) in visible light-illuminated Pt(IV)/TiO(2) dispersions. Spin-trap electron spin resonance (ESR) spectral results, measurement of quantities of organoperoxides formed, total organic carbon (TOC) and chemical oxygen demand (COD(Cr)) assays, together with XPS evidence show that the self-sensitized transformation dynamics of the EO dye mediated by Pt(IV)/TiO(2) are much faster than those occurring on naked TiO(2) under otherwise identical conditions of visible light irradiation. X-ray photoelectron spectral data also show that under the experimental conditions used, no Pt(0) formed on the titania particles during visible light irradiation. We propose a reaction mechanism in which the more rapid conversion of EO in the presence of PtCl(6) (2-) is caused principally by photoexcitation of the dye and not by localized excitation of the tetrachloroplatinate(IV)/TiO(2) particles.
authors.affiliation: Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.forename: Chuncheng
authors.initials: C
authors.lastname: Chen
authors.forename: Wanhong
authors.initials: W
authors.lastname: Ma
authors.forename: Jincai
authors.initials: J
authors.lastname: Zhao
authors.forename: Dianxun
authors.initials: D
authors.lastname: Wang
authors.forename: Hisao
authors.initials: H
authors.lastname: Hidaka
authors.forename: Nick
authors.initials: N
authors.lastname: Serpone