We investigate the photocatalytic performance of nanocomposites 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. The nanocomposites show enhanced photocatalytic activity, degrading up to 40% more pollutants with respect to the starting TiO2-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 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.
@article{arxiv.1903.05407,
title = {Photocatalytic activity of exfoliated graphite-TiO$_2$ nanocomposites},
author = {Gloria Guidetti and Eva A. A. Pogna and Lucia Lombardi and Flavia Tomarchio and Iryna Polishchuk and Rick R. M. Joosten and Alessandro Ianiro and Giancarlo Soavi and Nico A. J. M. Sommerdijk and Heiner Friedrich and Boaz Pokroy and Anna K. Ott and Marco Goisis and Francesco Zerbetto and Giuseppe Falini and Matteo Calvaresi and Andrea C. Ferrari and Giulio Cerullo and Marco Montalti},
journal= {arXiv preprint arXiv:1903.05407},
year = {2019}
}