Assessment of the Suitability of the One-Step Hydrothermal Method for Preparation of Non-Covalently/Covalently-Bonded TiO2/Graphene-Based Hybrids

Abstract

A hybrid nanocomposites containing nanocrystalline TiO2 and graphene-related materials (graphene oxide or reduced graphene oxide) were successfully prepared by mechanical mixing and the hydrothermal method in the high-pressure atmosphere. The presented X-ray photoelectron spectroscopy (XPS) study and quantitative elemental analysis confirm similar content of carbon in graphene oxide GO (52 wt% and 46 wt%, respectively) and reduced graphene oxide rGO (92 wt% and 98 wt%, respectively). No chemical interactions between TiO2 and GO/rGO was found. TiO2 nanoparticles were loaded on GO or rGO flakes. However, Fourier transform infrared-diffuse reflection spectroscopy (FTIR/DRS) allowed finding peaks characteristic of GO and rGO. XPS study shows that since the concentration of TiO2 in the samples was no less than 95 wt%, it was assumed that the interactions between TiO2 and graphene should not influence the lower layers of titanium atoms in the TiO2 and they occurred as Ti4+ ions. Hydrothermal treatment at 200 °C did not cause the reduction of GO to rGO in TiO2-GO nanocomposites. In general, the one-step hydrothermal method must be considered to be inefficient for preparation of chemically-bonded composites synthesized from commercially available TiO2 and unfunctionalized graphene sheets obtained from graphite powder.

Sustainable Jatropha Oil-Based Membrane with Graphene Oxide for Potential Application in Cu(II) Ion Removal from Aqueous Solution

“…Due to the reactivity of isocyanate versus different functional group, isocyanate had higher reactivity with the hydroxyl group compared to the other functional group of GO. In JPU/GO samples, the hydroxyl (-OH) band was found at 3675.84 cm −1 and 3675.56 cm −1 in JPU/GO 0.35 wt% and JPU/GO 0.50 wt% samples, respectively [59][60][61][62]. However, (-OH) stretching band in JPU/GO 0.65 wt% sample was reduced with the overlapping of (-NH) stretching.…”

Magnetic Resonance Studies of Hybrid Nanocomposites Containing Nanocrystalline TiO2 and Graphene-Related Materials

“…The nanocomposites named TiO 2 -1ButOH_A, TiO 2 -H 2 O-GO_5%_A, TiO 2 -1ButOH-GO_5%_A, TiO 2 -GO_5%_M, TiO 2 -H 2 O-rGO_5%_A, TiO 2 -1ButOH-rGO_5%_A, and TiO 2 -rGO_5%_M (where A means autoclave and M means mechanical mixing) were prepared utilizing the hydro- or solvothermal method under elevated pressure conditions (under autogenic pressure). The method of materials preparation and detailed characterization was presented in our previous paper [ 33 ]. In brief, the first group of samples was obtained by mechanical mixing of 4 g of starting TiO 2 with 5 wt.% of GO or rGO compounds (samples denoted with M–mechanical mixing).…”

“…Detailed XRD studies of the composites were conducted and discussed in the previous paper [ 33 ]. The samples contained almost only the anatase phase; the rutile content was lower than 1%.…”

Chemical- and Mechanical-Induced Lubrication Mechanisms during Hot Rolling of Titanium Alloys Using a Mixed Graphene-Incorporating Lubricant

“…Compared with the test results under experimental condition 1 with lubrication above, the lubrication film is uniform and continuous covered on the surface of the wear marks. Under the synergistic action of the lubricants, an effective barrier layer is formed on the surface of the friction pairs [44,45]. It effectively reduces the friction coefficient.…”