Solvothermal Reduction of Graphite Oxide Using Alcohols

Abstract

In the present work, we use either ethanol or ethylene glycol as reducing agents through the solvothermal method for graphite oxide reduction. A sulfuric acid treatment before the reduction process was also applied to evaluate its influence on the epoxy group ring-opening reaction. Reduced graphene oxide (RGO) samples were obtained with morphology like crumpled sheets. X-ray diffraction analyses (XRD) showed that the RGO produced via ethylene glycol (EG) reduction followed by treatment with sulfuric acid (RGOEGH) presented the largest d-spacing (0.4114 nm). For reduction with ethanol (RGOEt), the d-spacing value was 0.3883 nm. Infrared spectroscopy (FTIR) results indicated that RGOEt exhibited very low-intensity bands related to oxygenated functional groups, suggesting a high reduction degree, while the sample reduced with EG contained oxygen group bands in the spectrum that disappeared when H 2 SO 4 pretreatment was performed. Thermal gravimetric analyses (TGA) results showed that the samples present high stability and confirmed the reduction process. Moreover, the synthesized RGO sheets were comparable to those produced via more expensive and toxic methodologies.

Dentin Bond Integrity of Hydroxyapatite Containing Resin Adhesive Enhanced with Graphene Oxide Nano-Particles—An SEM, EDX, Micro-Raman, and Microtensile Bond Strength Study

“…The synthesized nano-GO particles were flake shaped, as observed via SEM in the study (Figure 1A). The reduction process of graphite to yield GO nanoparticles produces flake shaped particles or sheets with sharp edges due to the presence of oxygen groups in the oxide sheets, as reported previously by Soares et al [35]. In order to utilize maximum benefit of the addition of foreign filler particles in the adhesive, it is necessary that it is uniformly dispersed.…”

Reduced Graphene Oxide-Zinc Oxide Flower-Like Composite for Glass-Ionomer Materials Reinforcement

“…The x-ray diffraction pattern of GO ( Figure 3) presents a characteristic profile of a lamellar material. The peak at 2θ = 10.85° corresponds to an interlayer distance (d) of 0.814 nm, which is related to the introduction of oxygenated groups, confirming the oxidation process 39,40 . In the RGO sample, the peak at 10.85° disappears, which characterizes the reduction process, and a broad peak at 2θ = 25.5° appears, corresponding to an interlayer distance of 0.349 nm 39,41 .…”

“…FTIR spectrum of the synthesized GO presented in Figure 2 shows bands related to oxygenated groups: C=O at 1734 cm -1 ; C-OH at 1400 cm -1 ; and C-O at 1070 cm -1 , confirming the oxidation of graphite 39,40 . For RGO, it was observed a decrease in the intensity of these bands, due to the reduction process.…”

“…GO was separated by centrifugation and washed three times with hydrogen peroxide (10 wt%/v) and H 2 SO 4 (5 wt%/v), followed by washing with distilled water until pH 6. After, it was filtered in a 0.45 μm Nylon membrane and dried at 50 °C 39 . RGO was produced by thermal reduction of GO.…”

“…The morphology of the samples obtained by FEG-SEM analyses is presented in Figure 4. The micrography of GO ( Figure 4a) shows a sheet with wrinkles and folds, which is due to the interaction of oxygen groups present on the surface 39 . RGO exhibits a change in the morphology, caused by the reduction process.…”