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Efficient Photoinduced Conversion of an Azo Dye on Hexachloroplatinate( IV )‐Modified TiO 2 Surfaces under Visible Light Irradiation—A Photosensitization Pathway
Author(s) -
Zhao Wei,
Chen Chuncheng,
Ma Wanhong,
Zhao Jincai,
Wang Dianxun,
Hidaka Hisao,
Serpone Nick
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200204559
Subject(s) - photochemistry , x ray photoelectron spectroscopy , photocatalysis , visible spectrum , irradiation , titanium dioxide , photoexcitation , electron paramagnetic resonance , chemistry , materials science , catalysis , excitation , chemical engineering , organic chemistry , optoelectronics , nuclear magnetic resonance , physics , nuclear physics , engineering , metallurgy , electrical engineering
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.