Layer Graphene Sheets Research Articles

Synthesis of Few Layers Graphene Sheets from Graphite Rod via Electrochemical Exfoliation

Graphene has many excellent properties in mechanical strength, electrical conductivity, optical transparency and thermal conductivity. The basic unit of graphene is made of hexagonal ring of carbon shape. The production of graphene in large amounts can be done using conventional ways such as chemical vapour deposition (CVD). However, the cost production is very high due to high reaction temperature. Therefore, electrochemical exfoliation could become a promising method in future because of its simple, low cost and large-scale production. Electrochemical method is performed in the manner by connecting the graphite rod to the positive terminal (anode) while the copper sheet is connected to the negative terminal (cathode) and both of were immersed into electrolyte with a distance between them. Then, due to the potential difference, the exfoliation of graphite into graphene sheets occurs. X-Ray Diffraction revealed that high amount of exfoliated graphene sheets was synthesized successfully where the peak was seen at approximately 26.60°. Fourier Transform Infrared confirmed the synthesized of graphene oxide (GO) sheets (by using H2SO4 as electrolyte) shows the higher intensity of O-H band because of strongest oxidation behaviour of H2SO4 acid among all electrolytes used in experiment. Besides. SEM images show that the morphologies of the exfoliated graphene sheets have stacked, flaky-like, wrinkled and crumpled structures.

EXPERIMENTAL INVESTIGATION OF AMINE-BASED GRAPHENE NANOSUSPENSION FOR CO2 ABSORPTION

Absorption is the most widely used carbon dioxide (CO2) removal technology. The CO2 absorption performance of monoethanolamine (MEA), the most commonly used CO2 absorbent, can be improved by suspending nanoparticles. This work examined the performance of graphene nanoplatelets (GNPs) as additives to enhance CO2 absorption in MEA. The GNPs were characterized by HRTEM, FTIR, and XRD. The study examined the influence of GNP concentrations on CO2 absorption at room temperature. The images from HRTEM confirmed that the implemented graphene consists of several layers of graphene sheets. Increasing the loading of particles increased the solubility of CO2 until the optimum concentration was reached. From this work, it is evident that incorporating GNPs into MEA enhances the CO2 absorption performance of MEA. Thus, the addition of nanoparticles to the absorbent can enhance its CO2 absorptivity.

Two-photon absorption induced optical limiting action of Ag-doped lanthanum molybdate decorated reduced graphene oxide nanocomposites

In this research, we aimed to investigate the linear and non-linear optical properties of Ag-La2(MoO4)3@RGO nanocomposites. For this purpose, Graphene Oxide (GO) was synthesized by Modified Hummer’s method after which GO was chemically reduced to Reduced graphene oxide (RGO). The nanocomposite Ag-doped La2(MoO4)3 is prepared by a simple and facile co-precipitation method. The prepared nanocomposite was characterized by Fourier transform infrared (FTIR), Ultraviolet-Visible (UV-Vis) absorption, X-ray diffraction (XRD), Scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDX). XRD and EDX analysis indicated the reduction of GO and successful synthesis of Ag-doped La2(MoO4)3 nanocomposite. FESEM images portray the presence of thin layers of graphene sheets and Ag-doped La2(MoO4)3 on the sheets of reduced graphene oxide. Ground state absorption studies show that the reduction of graphene oxide causes a hypsochromic shift in the absorption maxima of the graphene layers. The photoluminescence of Ag- La2(MoO4)3@RGO demonstrates the utmost emission in the UV range caused by the valence band and conduction band's direct transitions in the band gap region. Z-scan method using Nd: YAG laser exposes that both nanocomposite and specific counterparts hold reverse saturable absorption behaviour. The source of optical limiting action is attributed to the excited state absorption process, emerging from the influence of the plasmon resonance state of Ag nanoparticles. Strong nonlinear absorption and lower onset limiting threshold make the Ag-La2(MoO4)3@RGO nanocomposite desirable material for laser safety devices.

Respiratory Toxicology of Graphene-Based Nanomaterials: A Review.

Graphene-based nanomaterials (GBNs) consist of a single or few layers of graphene sheets or modified graphene including pristine graphene, graphene nanosheets (GNS), graphene oxide (GO), reduced graphene oxide (rGO), as well as graphene modified with various functional groups or chemicals (e.g., hydroxyl, carboxyl, and polyethylene glycol), which are frequently used in industrial and biomedical applications owing to their exceptional physicochemical properties. Given the widespread production and extensive application of GBNs, they can be disseminated in a wide range of environmental mediums, such as air, water, food, and soil. GBNs can enter the human body through various routes such as inhalation, ingestion, dermal penetration, injection, and implantation in biomedical applications, and the majority of GBNs tend to accumulate in the respiratory system. GBNs inhaled and substantially deposited in the human respiratory tract may impair lung defenses and clearance, resulting in the formation of granulomas and pulmonary fibrosis. However, the specific toxicity of the respiratory system caused by different GBNs, their influencing factors, and the underlying mechanisms remain relatively scarce. This review summarizes recent advances in the exposure, metabolism, toxicity and potential mechanisms, current limitations, and future perspectives of various GBNs in the respiratory system.

Carbon-coated silicon/graphite oxide composites as anode materials for highly stable lithium-ion batteries.

Silicon (Si) has been widely investigated as an anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity. However, the huge volume expansion and low electrical conductivity limit its practical application to some extent. Here, we prepared silicon/reduced graphene oxide/amorphous carbon (Si/G/C) anode materials for lithium-ion batteries using a facile synergistic cladding layer. The protective effect of different carbon layers was explored and it was found that ternary composites have excellent electrochemical properties. In this work, the surface of Si was first modified using ammonia, and the positively charged Si was tightly anchored to the graphene sheet layer. In contrast, amorphous carbon was used as a reinforcing coating for further coating to synergistically build up the cladding layer of Si NPs with graphene oxide. The ternary composite (Si/G/C) material greatly ensures the structural integrity of the composites and shows excellent cycling as well as rate performance compared to Si/reduced graphene oxide and Si/carbon composites. For the Si/G/C composite, at a current density of 1 A g-1, it can be stably cycled over 267 times with 70% capacity retention (only 0.0711% capacity reduction per cycle).

Identification of microbes using single-layer graphene-based nano biosensors.

Graphene based nano sensors have huge potential in an era of sensor technology. The objective of this study is to create a sensor by investigating the vibration responses of cantilever and bridged boundary conditioned single layer graphene sheets (SLGS) with various attached microorganisms on the tip and at the centre of the sheet. The Parvoviridae, Flaviviridae, and Polyomaviridae biological substances have been comprehensively investigated here. For the Parvoviridae, Polyomaviridae, and Flaviviridae categories of targeted microbes, the sizes are 21nm, 40nm, and 45nm, respectively. The Parvoviridae family has a maximum frequency of 1.87x107 Hz with a cantilever condition and a mass of 4.2441 Zg, and for a bridged condition, it demonstrates a maximum frequency of 1.23x108 Hz with the same mass on armchair SLG (5 5). The data analysis shows that 3.0041 Zg mass of the Mimivirus has the lowest frequency. It demonstrates explicitly that the rate of frequency decreases as the value of mass increases. When compared to chiral SLG, the armchair single layer graphene sheet performs better. The research indicates that the dynamic properties are significantly influenced by the mass of various biological organisms. The application of this sensor will enable the detection of microorganisms or viruses that can be connected to SLG. In this research, the application of Single Layer Graphene (SLG) as a virus sensing device is explored. Atomistic finite element method (AFEM) has been used to carry out the dynamic analysis of SLG. Molecular dynamic analysis and simulations have been performed to see how SLG behaves when employed as sensors for biological entities and when they are exposed to bridged and cantilever boundary conditions. The frequency analysis was performed using ANSYS APDL software. SLG of various chirality has been utilised in the investigation. By altering the applied mass of a biological object, the difference in frequency observed. The idea behind mass detection employing nano biosensors is built on the concept that the stiffness of a biomolecule changes as its mass changes, making the resonant frequency extremely sensitive to that change. A shift in the resonance frequency results from a change in the associated mass on the graphene sheet. The main challenge in mass detection is estimating the variation in resonant frequency driven by the mass of the connected molecule. The SLG-based biosensor has a specific application in the early identification of diseases. The biosensor investigated in this article is novel, whereas the biosensors that are presently on the market operate using the ionization method. The simulations result shows SLG based biosensor's sensitivity considerably faster than an existing one.

Covalent graphene-diamond heterostructure coating on tool surface with enhanced lubricity and anti-wear performance

Graphene possesses extraordinary mechanical strength while it is difficult to integrate graphene layers on macroscale mechanical components due to the weak adhesion strength. In this work, we integrated a top layer of graphene sheets on the diamond-coated tool through in-situ growth of graphene on the diamond grains. With the aid of liquid metal catalyst, ultrastrong C–C covalent bonds are formed in the graphene-diamond interface, which can radically eliminate the peeling off of graphene sheets due to the insufficient adhesion strength. Cutting tests revealed that this top-layer graphene can substantially reduce cutting force and tool flank wear when cutting high-silicon aluminum alloy, with the reduction respectively reaching 40 % and 20 %. During the machining process, the graphene sheets are flattened and they gradually form a compact layer covering on the diamond surface, which can not only lubricate the tool surface but also protect the diamond from wear with the ultrahigh intrinsic strength. Further cutting experiments demonstrated that the effectiveness of the graphene sheets can sustain over 3600 m of cutting distance. The achievement in this work provides a novel insight into the integration of covalent graphene-diamond heterostructures in mechanical systems/devices with outstanding macroscale lubricity and anti-wear performance.

Green synthesis of Ag and Au NPs decorated rGO nanocomposite for high impedimetric electrochemical sensor as well as enhanced antimicrobial performance against foodborne pathogens

In the present study, Allium cepa L. leaves extract mediated silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) decorated reduced graphene oxide (Ag/Au/rGO NC’s) were synthesized and demonstrated their biological and electrochemical sensing applications. Interestingly, the synthesis of AgNPs and AuNPs was achieved rapidly within 1 h and 4 h, respectively. Whereas the production of both reduced graphene oxide (rGO) and Ag/Au/rGO NC’s was achieved at 96 h. The achieved results from the UV–Vis spectrum of 432 nm for AgNPs and 550 nm of AuNPs and the shifting of the characteristic GO absorption band of 230 nm into 270 nm as well as an absence of 305 nm confirmed the rGO synthesis. In addition, HR-XRD analyses confirmed the JCPDS file No. 04–0783 and 01–1174 pertaining to Ag and Au NPs. Further, the Raman spectroscopy, FT-IR and EDS analyses confirmed the evidence of nanomaterials biosynthesis. A polydisperse, spherical shaped average size AgNPs of 1 to 30 nm, spherical and triangular shaped AuNPs with an average size of 1 to 120 nm, and silk like appearance of a thin layered graphene sheet in rGO were observed through TEM. Also, the recorded results evident the uniform decoration of Ag and Au NPs into the rGO sheet. The electrochemical properties of as-synthesized materials were studied by electrochemical impedance spectroscopic (EIS) and cyclic voltammetry (CV) techniques. Interestingly, the Ag/Au/rGO NC’s modified electrode exhibited higher electrical conductivity and good electrocatalytic properties towards the electrooxidation of nitrite in a neutral medium than other nanomaterials. Eventually, Ag/Au/rGO NC’s confirmed the enhanced antibacterial against Gram-negative bacteria and dose dependent antifungal inhibitory activities against foodborne fungal pathogens of Fusarium graminearum, Alternaria alternata, and phytopathogenic fungus of Curvularia lunata and Sclerotinia sclerotiorum at the maximum tested conc. of 2 mg/mL, compared to other nanomaterials. From the result of zebrafish embryotoxicity (ZET), the highest toxicity was observed for AgNPs at 0.19 μg/mL. But in the case of Ag/Au/rGO NC’s the reduced toxicity was observed. Hence, the achieved results concluded the Ag/Au/rGO NC’s could be suitable for development of both as biomaterials for biomedical and effective sensors for environmental applications.

Graphene/Heterojunction Composite Prepared by Carbon Thermal Reduction as a Sulfur Host for Lithium-Sulfur Batteries.

An interlayer nanocomposite (CC@rGO) consisting of a graphene heterojunction with CoO and Co9S8 was prepared using a simple and low-cost hydrothermal calcination method, which was tested as a cathode sulfur carrier for lithium-sulfur batteries. The CC@rGO composite comprises a spherical heterostructure uniformly distributed between graphene sheet layers, preventing stacking the graphene sheet layer. After the introduction of cobalt heterojunction on a graphene substrate, the Co element content increases the reactive sites of the composite and improves its electrochemical properties to some extent. The composite exhibited good cycling performance with an initial discharge capacity of 847.51 mAh/g at 0.5 C and a capacity decay rate of 0.0448% after 500 cycles, which also kept 452.91 mAh/g at 1 C and in the rate test from 3 C back to 0.1 C maintained 993.27 mAh/g. This article provides insight into the design of cathode materials for lithium-sulfur batteries.

Quantum size effects in stacked multilayer graphene

In this paper,we study the quantum size effects in multilayer graphene sheets using first principles methods within the framework of density functional theory. Four different types of functionals are adopted respectively to describe the van der Waals interactions between graphene layer sheets: the DFT-GGA(PBE), the DFT-D2, the vdW-DF and the optPBE-vdW. By inspecting the binding energy as a function of increasing graphene layers, we find that the PBE functional can not well describe the van der Waals interactions between different layers of graphene sheets. In contrast, the other three methods exhibit similar results with monotonic increasing binding energy as a function of graphene layers towards the bulk limit, concluding that the layered graphene structure is stabilized by van der Waals interactions. The density of states at zero temperature indicate that the multilayer graphene sheets is a semi-metal, which is independent of sheet layers number. The finite temperature (about 200 K) density of states at Fermi surface are studied as a function of the number of stacking graphene layers. The systematic oscillating behavior of finite temperature density of states between odd and even number of layers is a demonstration of quantum size effects. The Fermi wavelength will converge to two times the inter-layer distance of graphite, which is consistent with the theory describing the motion of particles in a quantum well. Finally, we study the adsorption of single H atom on multilayer graphene sheets to test the role of quantum size effects. The adsorption energies and the vibration frequencies are calculated for comparison with experiments. Our results shed light on understanding the stacking process of multilayer graphene in vacuum both theoretically and experimentally.

Controlling solar radiation forces with graphene in plasmonic metasurface

Controlling and harvesting solar radiation pressure is a significant challenge, however, there are a few potential solutions, which are suitable for several key applications. In this study, an electrically tunable plasmonic metasurface is designed for the visible spectrum. Moreover, the normal and the tangential optical forces acting on the metasurface are calculated. Whilst presenting high efficiency in the anomalous reflection, the designed active metasurface provides tunability of optical forces acting on the metasurface. The metasurface is composed of tapered silver cells embedded on top of the graphene layer with 20 layers of graphene sheets. Hence, the transferred momentum to the metasurface can be controlled by tuning the Fermi level of graphene sheets. Our results can provide a suitable platform for optical force control desired in tunable radiation pressure harvesting, micro vehicles, solar sailing, and optical tweezers.

Highly Stable Potassium Metal Anodes with Controllable Thickness and Area Capacity.

K metal battery is a kind of high-energy-density storage device with economic advantages. However, due to the dendrite growth and difficult processing characteristics, it is difficult to prepare stable K metal anode with thin thickness and fixed area capacity, which severely limits its development. In this work, a multi-functional 3D skeleton (rGCA) is synthesized by simple vacuum filtration and thermal reduction, and K metal anodes with controllable thickness and area capacity (K content) can be fabricated by changing the raw material mass and graphene layer spacing of rGCA. Moreover, the graphene sheet layer of rGCA can relax stress and relieve volume expansion; carbon nanotubes can serve as the fast transport channel of electrons, reducing internal impedance and local current density; Ag nanoparticles can induce the uniform nucleation and deposition of K+ . The K metal composite anodes (rGCA-K) based on the conductive skeleton can effectively suppress dendrites and exhibit excellent electrochemical performance in symmetric and full cells. The controllable fabrication process of stable K metal anode is expected to help K metal batteries move toward the stage of commercial production.

Eco-friendly synthesized few layered graphene: 
 Main physico-chemical nanocharacterizations for optical quenching applications

The importance of green process in the synthesis of nanomaterials becomes universally known. In this study, we report on the efficiency of a Aspalathus linearis’s plant extract known as Rooibos tea on the synthesis of graphene via a bio-active process. Using several nanocharcterization techniques, our investigations on the main physico-chemical properties confirmed the ability of this plant extract as a reducing and capping agent on the synthesis of good quality few layered graphene sheets compared to several natural extracts and chemical agents. Furthermore, this eco-friendly cost-effective process allows the control and modulation of the optical and electrical properties of the prepared graphene. Moreover, this material was positively tested as silver NPs fluorescence quencher. Hence, Rooibos shows its ability as an effective chelating agent in the production of graphene sheets which serves electronic and optoelectronic related quenching applications.

Study on the microstructure and mechanical properties of microwave sintered NbC–Ni cermets reinforced by multilayer graphene

In recent years, NbC–Ni cermets has been proposed as a potential substitute for WC-Co cemented carbide in machining and other fields because of its economy and good performance, which has attracted extensive attention of scholars. Research on improving its mechanical properties will help to explore its application potential. Graphene-reinforced NbC–Ni cermets were prepared using a microwave sintering technique, and the effects of multilayer graphene (MLG) on its mechanical properties and microstructure were investigated. The experimental results show that the addition of a certain content of graphene contributes to the densification of the material and inhibits the grain growth. The Vickers hardness, toughness, and bending strength increased and then decreased with an increase in the MLG content. When 0.75 wt% MLG was added, the comprehensive mechanical properties of NbC–Ni cermets were optimal, with a Vickers hardness, fracture toughness, and bending strength of 1297.5 kg/mm2, 18.23 MPa m1/2, and 1464.5 MPa, respectively, which were 12.01%, 38.95%, and 18.97% higher than those without MLG. At low MLG content, the graphene sheet layers were well dispersed in the matrix grain boundaries, whereas graphene agglomerates and pores appeared in cermets with 1 wt% MLG, which degraded their mechanical properties. The strengthening and toughening mechanisms of MLG include grain refinement, large-angle deflection of cracks, crack bridging, and pullout of graphene sheet layers.

Electrochemical Performance of SnS@Graphene Composites Prepared by Deep Eutectic Solvent Method

SnS material is considered as an attractive anode material to substitute commercial graphite anodes of lithium‐ion batteries (LIBs) due to its large capacity, low cost, and environment‐friendliness. However, the side reactions induced during charge/discharge processes significantly expand the volume of SnS material, limiting its development. Herein, a novel deep eutectic solvent is synthesized with polyethylene glycol and SnCl2·2H2O, and SnS@graphene composites are prepared using a one‐step pyrolytic vulcanization method. The composite material is sandwich‐shaped with graphene sheet layers interspersed with SnS particles. Tests after making them into button cells have shown that the composite electrodes have excellent electrochemical properties: an initial discharge capacity of 1346 mAh g−1 at the current density of 100 mA g−1; outstanding long‐period performance under high current. In the case of 1 A g−1, it still has 421.8 mAh g−1 capacity after 1000 cycles. It also shows superior rate characteristics: under the current density of 5 A g−1, its specific discharge capacity is 343 mAh g−1; the specific discharge capacity increases rapidly to 798 mAh g−1 when the current density returns to 1 A g−1.

Molecular dynamic studies into the comparative optimization of thermo-mechanical characters of nano-composites of Ag and Cu reinforced by Graphene.

This article fundamentally aims at the comparative study of thermo-mechanical characters of Gr/Ag and Gr/Cu nano-composites. For demonstration purposes, three dimensions that is, (1 0 0), (1 1 0) and (1 1 1), of the metals attached with single layer Graphene sheet are considered. The study is facilitated by the adaptation of the molecular dynamic simulations of the soft LAMMPS to mimic the broad range of experimental environment. The attributes of each structure and their orientations are elaborated over wide range of experimental states, encompassing temperature ranging from 300 K to 1500 K, to assess the melting behavior. The thermal and structural properties are explored by employing mean square displacement (MSD) and radial distribution function (RDF). Furthermore, the mechanical characters are elaborated along both arm-chair and zigzag directions. The findings are supported by producing relevant graphical displays of stress-strain curves and generating extravagant depictions of various dislocations with the application of visual molecular dynamics (VMD) tool. On the basis of intense and careful computational investigations, we witnessed that the Gr/Cu (1 1 1) orientation produced most profound melting characteristics along with distinctive strengthening and fracture mechanism. These outcomes are consistent in comparison of both Gr/Metals layered structures and also with respect to all considered metallic orientations. The findings are discussed thoroughly in a well-structured and synchronized fashion throughout the article.

Long-term stable solid concentrated graphene dispersion assisted by a highly aromatic ionic liquid

HypothesisThe sonochemical exfoliation of graphite in solution has been demonstrated as a promising and easy technique for producing graphene dispersions. This is usually done in organic solvents and leads to unstable dispersions with very low graphene concentration. Ionic liquids (ILs) represent a versatile and safe alternative to traditional organic solvents. A few recent studies reported the use of commercial ILs with bulky anions, such as bis(trifluoromethylsulfonyl)imide, and aromatic cations, such as imidazolium, which favour the exfoliation of graphite through π-π and cation-π interactions. Although recently investigated, the role of aromatic groups on imidazolium cations is still controversial and systematic studies are still necessary. Besides, these studies were limited to liquid dispersions at room temperature. ExperimentsHerein, we prepared four highly aromatic imidazolium-based ILs, including the newly reported 1-(naphthylmethyl)-3-benzylimidazolium bis(trifluoromethanesulfonyl)imide, [(Np)(Bn)im][NTf2]. These ILs were used for the sonochemical exfoliation of graphite and compared with a commercial benchmark, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [Bmim][NTf2]. FindingsInterestingly, [(Np)(Bn)im][NTf2] allowed reaching solid dispersions at room temperature containing thin few layer graphene sheets with long-term stability (up to 2 years) and high concentration (3.6 mg/mL). Such graphene dispersion combines long-term stability in the solid-state and high processability in the liquid state, by a simple heating above 60 °C.

On the Mechanical Buckling Analysis of FG-GRC Laminated Plates with Temperature-Dependent Material Properties Using Isogeometric Approach

In this paper, the isogeometric method is developed to study mechanical buckling behavior of nanocomposite plates reinforced by graphene sheets with temperature-dependent (TD) material properties in thermal environment. The plate is separately subjected to in-plane uniaxial, biaxial and shear loadings. It is assumed that the plate has different number of layers. By considering different volume fraction for each layer of graphene sheets, different functionally graded (FG) patterns of graphene sheets may be achieved. Furthermore, in some cases, it is considered that more than one FG patterns exist along the plate thickness. The energy statement of the plate is obtained using a logarithmic higher-order shear deformation theory (HSDT). Then, the isogeometric method is used to establish the desired eigenvalue problem. The comparison and convergence studies are presented for a wide range of numerical examples in all considered cases to show the correctness and ability of the solution. Afterwards, by presenting a set of numerical examples, the effects of plate significant parameters on the critical buckling load of the plate are examined. It is shown that the highest critical buckling loads occur when the plate has the minimum number of layers.

Dynamic analysis of single–layered graphene sheet subjected to a moving nanoparticle: A molecular dynamics study

The dynamic response of a single–layered graphene sheet (SLGS) subjected to a moving nanoparticle is investigated based on the molecular dynamics (MD) simulations. The time history and maximum value of the sheet’s central point deflection are considered as two main indices and reported under various circumstances. The MD simulation has the ability to provide the time history and maximum value of the central deflection along with the vibration behavior of the GS under a moving nanoparticle. The effect of the sheet’s parameters, such as dimensions, surface tension, and boundary conditions, as well as the nanoparticle’s parameters, including dimensions and velocity, on the dynamic response of the sheet is studied. It was found that the velocity of the nanoparticle does not significantly affect the deflection of the GS, while the boundary conditions and aspect ratio of the sheet have a noticeable impact on the dynamic and vibrational behavior of the GS.

Study on the microstructure of the symbiosis of coal-based graphene and coal-based graphene quantum dots: preparation and characterization

Coal-based graphene sheets (GS) and coal-based graphene quantum dots (GQDs) are usually prepared separately. In this paper, symbiosis of coal-based GS and coal-based GQDs was successfully prepared with our proposed preparation method by using three raw coals with different reflectance (collected from Qinshui coalfield, Shanxi Province) as carbon sources. The results showed that coal-based GS and coal-based GQDs can exist stably in the symbiosis and are distributed in different layers, and the GQDs are freely distributed between layers of GS. The average number of GS (N ave) in the three symbiosis is about 7 and the average interlayer spacing (d 002) is about 0.3887 nm. The average diameter of GQDs in the three symbiosis is about 4.255 nm and the average d 002 is about 0.230 nm. The average N ave of the three symbiosis was about 3 and the average d 002 is about 0.361 nm. The morphology and crystal parameters of symbiosis is more similar to that of graphene, the elements are only carbon and oxygen. In the prepared symbiosis, the higher the reflectance of raw coal, the smoother the lattice skeleton and the less vortex-layer structure of GS, and the larger the diameter and the denser the six membered ring of GQDs. The C and O functional groups of the prepared symbionts are similar. The higher the reflectance of coal, the higher the content of C–C/C=C. Under ultraviolet light, the prepared products all emit blue, and the higher the reflectance of coal, the higher the ultraviolet absorption, and the stronger the fluorescence intensity.