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arXiv · 1903.05407

Photocatalytic activity of exfoliated graphite-TiO$_2$ nanocomposites

Gloria Guidetti·Eva A. A. Pogna·Lucia Lombardi·Flavia Tomarchio·Iryna Polishchuk·Rick R. M. Joosten·Alessandro Ianiro·Giancarlo Soavi·Nico A. J. M. Sommerdijk·Heiner Friedrich·Boaz Pokroy·Anna K. Ott·Marco Goisis·Francesco Zerbetto·Giuseppe Falini·Matteo Calvaresi·Andrea C. Ferrari·Giulio Cerullo·Marco Montalti
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Abstract

We investigate the photocatalytic performance of nanocomposites prepared in a one-step process by liquid-phase exfoliation of graphite in the presence of TiO$_2$ nanoparticles (NPs) at atmospheric pressure and in water, without heating or adding any surfactant, and starting from low-cost commercial reagents. The nanocomposites show enhanced photocatalytic activity, degrading up to 40$\%$ more pollutants with respect to the starting TiO$_2$-NPs. 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 TiO$_2$ 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.

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Gloria Guidetti, Eva A. A. Pogna, Lucia Lombardi, Flavia Tomarchio, Iryna Polishchuk, Rick R. M. Joosten, Alessandro Ianiro, Giancarlo Soavi, Nico A. J. M. Sommerdijk, Heiner Friedrich, Boaz Pokroy, Anna K. Ott, Marco Goisis, Francesco Zerbetto, Giuseppe Falini, Matteo Calvaresi, Andrea C. Ferrari, Giulio Cerullo, Marco Montalti. 2019-03-13. Photocatalytic activity of exfoliated graphite-TiO$_2$ nanocomposites. https://arxiv.org/abs/1903.05407

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