Highly-efficient photocatalytic generation of superoxide radicals by phase-pure rutile TiO2 nanoparticles for azo dye removal
| Autor: | Sakina Bouderias, Mirko Prato, László Kőrösi, Balázs Bognár, Alice Scarpellini, Lea Pasquale, Andrea Castelli |
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| Rok vydání: | 2019 |
| Předmět: |
Anatase
Spin trapping Radical General Physics and Astronomy Nanoparticle 02 engineering and technology Surfaces and Interfaces General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Photochemistry 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films chemistry.chemical_compound chemistry Rutile Photocatalysis Methyl orange 0210 nano-technology Photodegradation |
| Zdroj: | Applied Surface Science. 493:719-728 |
| ISSN: | 0169-4332 |
| Popis: | The photocatalytic activity of TiO2 polymorphs has been frequently debated in literature. Numerous studies reported that rutile TiO2 exhibits low photocatalytic activity, and it is generally accepted that rutile has lower photoactivity than the anatase phase. Herein, we studied the photocatalytic activity of phase-pure rutile TiO2 nanoparticles prepared via microwave-assisted hydrothermal method (MW-R NPs). The syntheses were performed with relatively short reaction time (1−3h) at 180 °C using a microwave digestion system. The samples were characterized in detail and then tested in the photodegradation of methyl orange (MO). We demonstrate that the photodegradation of MO with MW-R NPs is highly efficient in the presence of H2O2. By employing 4.4 mM H2O2, ~90% of total decolorization was achieved after 2 min of UV-A irradiation. At the same experimental conditions, MO degradation with Degussa P25 TiO2 was only ~7%. The superior photoactivity of MW-R NPs was related to the effective photogeneration of O2•− radicals as revealed by EPR investigation. These rutile nanoparticles are excellent photocatalysts in the presence of H2O2, signifying that this oxygen source react easily with the photogenerated holes on the MW-R NPs, and thus the interfacial charge transfer lead to the formation of a large amount of O2•− radicals. |
| Databáze: | OpenAIRE |
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