Photocatalytic activity of exfoliated graphite–TiO2 nanoparticle composites

We investigate the photocatalytic performance of composites prepared in a one-step process by liquid-phase exfoliation of graphite in the presence of TiO2 nanoparticles (NPs) at atmospheric pressure and in water, without heating or adding any surfactant, and starting from low-cost commercial reagent...

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Bibliographic Details
Published in:Nanoscale 2019-11, Vol.11 (41), p.19301-19314
Main Authors: Guidetti, Gloria, Pogna, Eva A A, Lombardi, Lucia, Tomarchio, Flavia, Polishchuk, Iryna, Joosten, Rick R M, Ianiro, Alessandro, Soavi, Giancarlo, Nico A J M Sommerdijk, Friedrich, Heiner, Pokroy, Boaz, Ott, Anna K, Goisis, Marco, Zerbetto, Francesco, Falini, Giuseppe, Calvaresi, Matteo, Ferrari, Andrea C, Cerullo, Giulio, Montalti, Marco
Format: Article
Language:English
Subjects:
Catalytic activity
Composite materials
Electron transfer
Exfoliation
Graphite
Liquid phases
Nanoparticles
Nitrogen oxides
Photocatalysis
Photodegradation
Physics
Pollutants
Reagents
Titanium dioxide
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Summary:We investigate the photocatalytic performance of composites prepared in a one-step process by liquid-phase exfoliation of graphite in the presence of TiO2 nanoparticles (NPs) at atmospheric pressure and in water, without heating or adding any surfactant, and starting from low-cost commercial reagents. These show enhanced photocatalytic activity, degrading up to 40% more pollutants with respect to the starting TiO2-NPs, in the case of a model dye target, and up to 70% more pollutants in the case of nitrogen oxides. In order to understand the photo-physical mechanisms underlying this enhancement, we investigate the photo-generation of reactive species (trapped holes and electrons) by ultrafast transient absorption spectroscopy. We observe an electron transfer process from TiO2 to the graphite flakes within the first picoseconds of the relaxation dynamics, which causes the decrease of the charge recombination rate, and increases the efficiency of the reactive species photo-production.
ISSN:2040-3364
2040-3372
DOI:10.1039/c9nr06760d