Synthesis of RGO/TiO2 nanocomposite flakes and characterization of their unique electrostatic properties using zeta potential measurements

The study aimed at describing the influence of the modification of the electrostatic properties of titanium dioxide (TiO2) nanoparticles by their in situ deposition on the surface of reduced graphene oxide (RGO). For RGO/TiO2 (40 wt%) nanocomposite flake synthesis, we have developed the innovative simplified sol-gel method which is followed by the thermal decomposition of the organic precursor (the intermediate product). The investigation results confirmed that the TiO2 nanoparticles (ca. 94 nm) that covered the surface of RGO existed mostly in the form of hexagonal anatase nanocrystals and were covalently bonded to the RGO surface. The layer of TiO2 nanoparticles acted as an effective spreader between individual RGO flakes. The deposition of TiO2 nanoparticles resulted in a 40% increase of the BET specific surface area of GO. In our study, we show that the deposition of TiO2 nanoparticles on the surface of RGO flakes modifies their electrostatic properties. This suggests that RGO flakes influence the zeta potential of the RGO/TiO2 (40 wt%) surface which would be composed only of TiO2 (contrary to the theory of charged surface sights). The influence of RGO on zeta potential measured on the surface of RGO/TiO2 (40 wt%) nanocomposite flakes was most visible in a distilled water environment and a sodium chloride solution.