Efficient Photoinduced Conversion of an Azo Dye on Hexachloroplatinate(IV)-Modified TiO2 Surfaces under Visible Light Irradiation—A Photosensitization Pathway
✍ Scribed by Wei Zhao; Chuncheng Chen; Wanhong Ma; Jincai Zhao; Dianxun Wang; Hisao Hidaka; Nick Serpone
- Book ID
- 101831330
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 184 KB
- Volume
- 9
- Category
- Article
- ISSN
- 0947-6539
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✦ Synopsis
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.