Preparation and Characterization of Reduced Graphene Oxide/Titanium Dioxide Composites by Hydrothermal Method

Abstract

In the present work, reduced graphene oxide/Titanium dioxide (rGO/TiO2) composites (1:1 and 1:2 wt %) have been synthesized by the hydrothermal method using graphene oxide (GO) and commercial TiO2 as precursors. Previously, we prepared the GO, in the way optimizing and making safer, the Hummers route. We have chosen the hydrothermal method to prepare the composites because it offers several advantages: 1) It consist of a very simple experimental setup, 2) it utilizes only water, instead of Hydrazine or Sulfonate used as chemical reductants in traditional methods, avoiding the incorporation of un-willing impurities into GO sheets, 3) the temperature and pressure condition reached in the closed hydrothermal system have promoted the recovery of π-conjugation after dehydration diminishing defects concentration and increasing the degree of reduction of the GO sheets, and 4) this system is compatible with industrial batch production. The structure, surface morphology, chemical composition and optical properties of GO, TiO2 and rGO/TiO2 composites have been analyzed using, TEM, FTIR, Raman- and XPS-spectroscopy. TEM micrographs show that the TiO2 nanoparticles are non-homogenously adsorbed onto the GO sheets. FTIR spectra of the rGO/TiO2 composites suggest that during the hydrothermal process the GO sheets get reduced. Raman spectra suggest that TiO2 remains with anatase structure even after the hydrothermal process. The C 1s XPS spectra of the rGO/TiO2 composites have shown a significant decrease of oxygenated carbon related signals, confirming that most of the oxygenated groups were successfully removed. Based on these characterization results we infer that, GO sheets of good quality have been successfully synthesized and the GO sheets have been partially reduced via the TiO2 nanoparticles anchored during the hydrothermal process.