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Publication type: Article in scientific journal
Type of review: Peer review (publication)
Title: Strong activity enhancement of the photocatalytic degradation of an azo dye on Au/TiO2 doped with FeOx
Authors: Waheed, Ammara
Shi, Quanquan
Maeda, Nobutaka
Meier, Daniel Matthias
Qin, Zhaoxian
Li, Gao
Baiker, Alfons
et. al: No
DOI: 10.3390/catal10080933
Published in: Catalysts
Volume(Issue): 10
Issue: 8
Page(s): 933
Issue Date: 13-Aug-2020
Publisher / Ed. Institution: MDPI
ISSN: 2073-4344
Language: English
Subjects: Orange II; Operando; Photocatalysis; Au-FeOx/TiO2; Modulation; Excitation; Spectroscopy
Subject (DDC): 660: Chemical engineering
Abstract: The doping of Au/TiO2 with FeOx is shown to result in a strong enhancement of its photocatalytic activity in the degradation of the azo dye Orange II. In order to examine the source of this enhancement, Au-FeOx/TiO2 nanocomposites containing different molar ratios of Au:Fe were synthesized, and X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), and high-resolution transmission electron microscope (HRTEM) analyses indicated that the TiO2-supported Au nanoparticles were partially covered with an amorphous layer of FeOx species, in which the iron was present as Fe2+ and Fe3+. The metal-semiconductor system, i.e., Au/TiO2, showed only a moderate degradation rate, whereas doping with FeOx strongly enhanced the degradation activity. The bandgap energy decreased gradually from Au/TiO2 (3.13 eV) to the catalyst with the highest FeOx loading Au-FeOx (1:2)/TiO2 (2.23 eV), and this decrease was accompanied by a steady increase in the degradation activity of the catalysts. XPS analyses revealed that compared to Au/TiO2, on Au-FeOx/TiO2 a much higher population density of chemisorbed and/or dissociated oxygen species was generated, which together with the decreased bandgap resulted in the highest photocatalytic activity observed with Au-FeOx (1:2)/TiO2. The processes occurring during reaction on the catalyst surface and in the bulk liquid phase were investigated using operando attenuated total reflection IR spectroscopy (ATR-IR) combined with modulation excitation spectroscopy (MES), which showed that the doping of Au/TiO2 with FeOx weakens the interaction of the dye with the catalyst surface and strongly enhances the cleavage of the azo bond.
Fulltext version: Published version
License (according to publishing contract): CC BY 4.0: Attribution 4.0 International
Departement: School of Engineering
Organisational Unit: Institute of Materials and Process Engineering (IMPE)
Appears in collections:Publikationen School of Engineering

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