Graphene is a two-dimensional monolayer planar sheet containing carbon atoms that are sp2-bonded to one other and tightly packed in a honeycomb crystal structure. Because of its extraordinary qualities, graphene and its derivatives, such as functionalized graphene, graphene oxide (GO), and reduced graphene oxide (rGO), have attracted substantial attention in a variety of applications. The synthesis of graphene and its derivatives of high quality can be accomplished by the employment of a several different methods. When subjected to various reduction methods, GO and rGO emerge with distinctive sets of properties. These features, in turn, have an impact on the graphene’s overall usefulness and performance. This paper provides an overview of the influence that thermal annealing has on the structural and physical properties of graphene. Following the thermal annealing, GO was converted into rGO, and this allowed for the coherent crystal structure of rGO to be restored. It has been found that the annealing temperature has a direct relationship with the crystallite size. The results of the recorded Raman spectra demonstrate that the degree of imperfection ([Formula: see text] ratio) can sometimes be found to increase while at other times it can be found to decrease. There has not been any conclusive evidence to support either the hypothesis that annealing is employed to polish graphene or the hypothesis that this can lead to changes in doping, defect levels, and strain consequences. Additionally, the impact that thermal annealing has on the functionality and performance variations of rGO has been analyzed and explained. This study concluded with a concise review, a discussion of the challenges faced, and a discussion of the opportunities presented by the graphene.

The requirement for restoring graphene’s electrical and thermal properties necessitates the implementation of reduction processes that remove oxygen atoms from the surface of graphene oxide sheets. Nevertheless, has been reported that the synthesis of graphene with a minimal oxygen content remains an obstacle in the field of graphene synthesis. The partial restoration of the initial graphene characteristics brought on by the recombination of carbon–carbon double bonds is primarily constrained by the existence of leftover oxygen atoms and lattice flaws. However, the absence of polar dioxide-based groups of function makes it difficult for the substance to disperse. Oxygen-containing functional groups also serve as reaction sites to bond active molecules to reduce graphene sheets. The literature describes many chemical methods to reduce graphene oxide for these reasons. It’s crucial to choose a chemical method that allows a thin modulation of residual oxygen content to tune the end product’s properties. This research demonstrates a synthesis mechanism for the low oxygen-containing thermally reduced graphene oxide (T-R-GO) by employing an electrochemical technique, which is then followed by thermal reduction. An environment-friendly, eco-friendly, simpler, and scalable electrochemical approach was initially used to synthesize graphite oxide. A steady power source of 24[Formula: see text]V DC (direct current) has been applied while the exfoliation process is being carried out. It has been noticed that there is a potential difference of 1[Formula: see text]V during the process of exfoliation. This difference is because the electrochemical cell creates a resistance, which results in a potential difference. Within the muffle furnace, the preoxidized graphite was subjected to a thermal reduction process at a temperature of 900[Formula: see text]C. The microstructure, elemental composition, as well as C/O ratio (ratio of carbon and oxygen), was analyzed using field emission scanning electron microscopy (FESEM), transmission electron microscopy as well as energy dispersive X-ray (EDX). According to the results of EDX, reduction temperature serves a crucial role in the elimination of oxygen functionalities or their derived compounds. The surface topography and thermal stability analysis were analyzed using atomic force microscopy (AFM) and thermogravimetric analysis (TGA). The crystallinity and disorder in microstructure were investigated using X-ray powder diffraction (XRD) and Raman spectroscopy analysis. X-Ray data show that high-temperature annealing restored the RGO structure of the crystal. The interplanar distance is 3.824[Formula: see text]Å and the diffraction peak is 26.42[Formula: see text]. Raman bands measured the defect’s I[Formula: see text]/I[Formula: see text] ratio (intensity ratio) as 0.423. The Raman study shows that the flaws are minimal. This research offers a massive, economical, and environmentally friendly method for synthesizing graphene for use in industry.

A high-quality, bulk synthesis of graphene that is inexpensive, and environmentally safe is highly desired because of the broad range of applications. In comparison to the chemical vapor deposition (CVD) method, epitaxial growth on silicon carbide, etc., the electrochemical approach is thought to be the most straightforward and eco-friendly way for the cost-effective bulk production of graphene from graphite. Moreover, the thermal reduction method appears to be a particularly cost-effective way to eliminate oxygen-containing functional groups when compared to chemical reduction. The yield of graphene is also impacted by the choice of cathode low-cost, which is extremely important and played a critical role during the synthesis process. In this work, we demonstrate a green, eco-friendly, and cost-effective electrochemical method for the synthesis of reduced graphene oxide (RGO) followed by thermal reduction. To accomplish electrochemical exfoliation for the graphene synthesis, a constant DC power of 65[Formula: see text]W ([Formula: see text][Formula: see text]V and [Formula: see text][Formula: see text]amp) has been supplied within an electrolytic cell that contains 2[Formula: see text]M of sulphuric acid as an electrolytic solution. The aluminium has been utilized as a cathode in place of the platinum, carbon cathode, etc. Moreover, to prepare the electrolytic solution and for the sonication process, sterilized water has been used in place of DI (deionized water). Thereafter, previously oxidized graphite oxide has been thermally reduced at a temperature of [Formula: see text]C. The phase, crystallinity, and interatomic distance were investigated using X-Ray diffraction (XRD) analysis. X-Ray data show that the RGO crystal structure has been recovered following high-temperature annealing. The diffraction peak seems to be at [Formula: see text] with an interplaner distance of 3.48[Formula: see text]Å. The intensity of the defect, as measured by the [Formula: see text] ratio (intensity ratio), was analyzed using Raman spectra, and the result of that investigation was found to be 0.196. The findings of the Raman study unambiguously reveal that the severity of the defects is judged to be on the lower end of the spectrum. The surface texture, microstructure, and elemental analysis were performed using atomic force microscopy (AFM), Field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), and EDX analysis. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to determine the number of oxygen-containing functional groups that existed in the RGO sample and their thermostability. The results of FTIR and TGA analysis clearly demonstrate that the reduction temperature has a major role in determining the proportion of oxygen that is present in the graphene. This study presents a large-scale, cost-effective, and eco-friendly graphene synthesis method for industrial applications.