Graphene-based Composite Materials Research Articles

The research progress on photocatalytic performance of graphene-based nanocomposites

As soon as nanomaterials were discovered, they attracted a lot of attention because of their unique and excellent properties and became major hot research. They are regarded as the most promising materials in the 21st century. With the growth of industrial production, photocatalytic technology has been pursued as an efficient, green, and economical way of industrial production and treatment of pollution. However, the low light energy utilization of traditional semiconductor materials is a drawback that cannot be ignored. Graphene, as one of the most common and widely used 2D nanomaterials, has a special structure and characteristics that can effectively solve this problem. The paper briefly introduces the structure, properties, preparation method, and basic principle of photocatalysis of graphene. At the same time, a review is provided on the application of graphene-based composite materials in the field of photocatalysis, including dye degradation, photocatalytic treatment of other emerging pollutants, photocatalytic treatment of air pollutants, and water decomposition. By summarizing and integrating the photocatalytic properties of several graphene-based composites, this article lays the foundation and helps to discover new graphene composites.

Fused Filament Fabrication of Polyethylene/Graphene Composites for In-Space Manufacturing.

Graphene-based composite materials are highly sought after for space applications due to their ability to encompass various properties, such as electrical conductivity, thermal resistance, and radiation shielding. This versatility allows for the creation of multifunctional components that can serve various purposes in space. Three-dimensional (3D) printing of composite materials in space offers a versatile and efficient means of manufacturing components, tools, and structures that are tailored to the unique challenges and requirements of space missions. In this work, we aim to develop 3D-printed composites made of medium-density polyethylene (MDPE) matrix and exfoliated graphene nanoplatelets (xGnP) as filler, using fused filament fabrication (FFF). Our research focuses on the challenges associated with the FFF process for fabricating MDPE/xGnP materials, particularly by optimizing filament extrusion and assessing the resulting material properties and space environmental compatibility. Firstly, we optimize the extrusion process, and use the MDPE/xGnP filaments to fabricate 3D-printed samples after defining the FFF parameters. We employ differential scanning calorimetry (DSC) to assess the melting properties and crystallization degree of the extruded filaments and 3D-printed samples, providing insights into the relationship between these properties and the characteristics of the initial powders. Electrical and tensile tests are carried out to evaluate the material properties after successfully mitigating challenges, such as warping and inadequate adhesion, to build plates during the printing process. Finally, we subject the 3D-printed composites to outgassing tests under exposure to the AM0 solar spectrum to evaluate their space environmental suitability. The results of this work demonstrate the capability of the FFF-based process to efficiently manufacture components made of MDPE/xGnP composites, providing optimized parameters for their potential in-space fabrication.

The application of ferrous and graphitic N modified graphene-based composite cathode material in the bio-electro-Fenton system driven by sediment microbial fuel cells to degrade methyl orange

In this work, the ferrous (Fe2+) and graphitic N modified graphene-based composite cathode materials (N-rGO/Fe3O4) were developed through an in-situ reduction method, aiming to facilitate the two-electron pathway in the oxidation-reduction process. This approach generated a specific concentration of H2O2, enabling the construction of a sediment bio-electro-Fenton system using Fe2+ released from the cathode materials. Notably, this system operates without the need for proton exchange membranes. During the cathode material preparation, the utilization of Fe2+ as a reduction agent for graphene oxide (GO), triggered ammonia water to form graphitic N in graphene sheets. This addition enhanced the two-electron pathway, resulting in increased H2O2 production. Specifically, when the Fe2+ concentration was maintained at 0.1 mol/L, precise preparation of N-rGO/Fe3O4 occurred, leading to a maximum output voltage of 0.528 V and a maximum power density of 178.17 mW/m2. The degradation of methyl orange (MO) reached 68.91% within a 25-h period, a phenomenon contributed to the presence of graphitic N in the graphene sheets. H2O2, a byproduct of the two-electron pathway in cathode oxidation reduction reaction, played a crucial role in constructing the bio-electro-Fenton system. This system, in conjunction with Fe2+ released from N-rGO/Fe3O4, facilitated the complete degradation process of MO.

Composite porphyrin-based conjugated microporous polymer/graphene oxide capable of photo-triggered combinational antibacterial therapy and wound healing

Developing antibiotic-free treatment strategies to cope with the crisis on drug-resistant bacteria, are urgently needed. Antibiotics-independent physical approaches, especially the non-invasive phototherapies, worked through the assistance of photosensitizer (PS), have geared intensive attention and interests. Here, composite porphyrin-based conjugated microporous polymer/graphene oxide, denoted as GO-TAPP, combining the advantages of each component perfectly, was developed as broad-spectrum antibacterial agent. GO-TAPP, prepared via the self-oxidation coupling of tetraethynyl porphyrin on the surface of graphene oxide, could exert synergistic photothermal (PTT, ascribed to the graphene) and photodynamic (PDT, derived from the Porphyrin polymer) antimicrobial effectiveness. Both the in vivo and in vitro experiments have confirmed GO-TAPP are extremely potent against the Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) pathogens, which presents a remarkably enhanced sterilizing effect in comparison with its counterparts (the bare GO, and TAPP). Meanwhile, the synergistic effect of GO-TAPP could significantly accelerate the healing of open wound infected by bacterial. Altogether, this work proposed a new approach for the rational preparation of highly biocompatible graphene-based composite materials as antibiotic-free agents with synergistic antibacterial effect to combat bacterial infections.

Defect mediated lithium adsorption on graphene-based silicon composite electrode for high capacity and high stability lithium-ion battery

Carbon-coated silicon materials are considered as promising anode materials in high-capacity lithium-ion batteries (LIBs). Theoretically, using graphene as the anode material in the LIB would afford high electrical conductivity, mechanical stability of Si, and suppression of the unstable solid–electrolyte interface. However, its usage is hindered by its electrochemical characteristic, which is not electrochemically active when combined with lithium. Therefore, research on graphene as the anode and coated material in LIBs has been conducted using defect engineering to enhance the storage capacity of graphene. Although the electrochemical characteristics of various defects in graphene have been studied experimentally and theoretically, graphene-based composite anode materials such as graphene–silicon composite electrodes have rarely been studied from the electrochemical and mechanical perspectives. In this study, lithium adsorptions are conducted on various defected graphene and graphene–silicon composites using density functional theory calculation. The formation energies of Li on the various defected graphene are assessed, and the mechanical strengths of the graphene–silicon composites are analyzed. Our calculations validate that the defects in graphene enhance the electrochemical adsorptions and interfacial mechanical strengths of the graphene and graphene–silicon composites. During lithiation, the defects mediate greater interfacial adhesion of the silicon–graphene composite. Hence, we elucidate that defected graphene increases the electro-chemo mechanical stabilities of silicon composites in high-capacity LIBs.

Ionic modification of graphene nanosheets to improve anti-corrosive properties of organosilicon composite coatings.

Composite coatings with anti-corrosive properties were fabricated using quaternized silicone oil modified graphene oxide and silicone polymer. Quaternized silicone oil was successfully synthesized through copolymerization of octamethyl cyclotetrasiloxane (D4), chloropropylsilane and triethylamine. The quaternized silicone oil modified graphene oxide (M-GO) was characterized by using 1H NMR, FT-IR, Small-angle X-ray scattering (SAXS), Thermogravimetry (TG) and Transmission electron microscopy (TEM). The results showed that the M-GO was formed successfully. The M-GO could be dispersed without aggregation in some organic solvents, and the concentration of M-GO could be up to 3 mg ml-1. The M-GO-reinforced silicone composites exhibited obvious improvements in thermal stability, mechanical properties and especially anticorrosive properties with the highest E corr (-121 mV) and the lowest I corr (6.058 × 10-9 A cm-2), and the protection efficiency of the matrix could reach 99.97%. The anticorrosive mechanism of the fabricated composite coatings was investigated. This work provides a ready strategy for modification of GO and fabrication of high performance graphene-based silicone composite materials.

Role of interfacial contact between 2D materials and preselected nanostructures in the degradation of toxic dyes: Multifunctional facets of graphene

Designing intimate interfacial contact between nanostructures and two-dimensional (2D) materials is highly desirable to influence the movement of generated charge carriers. Nanostructured zinc oxide (ZnO) is a fascinating material with unique optical and electrical properties. 2D reduced graphene oxide (rGO) exhibits semiconductor behaviour with tunable catalytic activity and excellent biocompatibility. Hence, we have designed a hybrid material by selecting nanostructures of an oxide semiconductor (ZnO) with reduced graphene oxide (rGO) using a hard integration technique followed by a low-temperature hydrothermal route. The good encapsulation of rGO over the ZnO nanorods was confirmed by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. The photocatalytic activities of ZnO, rGO, and ZnO/rGO were studied under visible-light irradiation using three different toxic dyes, methylene blue (MB), methyl orange (MO), and Congo red (CR). The composite materials exhibited excellent efficiencies of 100, 95, and 90% for the degradation of MB, MO, and CR, respectively. Moreover, the degradation of the dye was found to follow first-order kinetics. The enhanced efficiencies are attributed to the adsorption and efficient charge transfer from rGO to the conduction band of ZnO. The role of the multifunctional facets of graphene was presented to elucidate the visible-light activity of the composite materials for enhanced efficiency. The main reactive species (e−) of the reduction reaction were confirmed through a radical trapping experiment, which showed the generation of highly reactive •OH radicals that decompose the toxic dye. The results provide a perspective for developing graphene-based composite materials with desired preselected nanostructures for solar energy utilisation.

Interlayer shear coupling in bilayer graphene

The interfacial shear coupling (ISC) governs the relative in-plane deformations of layered two-dimensional (2D) van der Waals (vdW) materials, which is significant for both the fundamental theory of solid mechanics and the stability design of 2D devices. Here we study the representative ISC of 2D vdW stacks using bilayer graphene (BLG) and isotope-labeled Raman spectroscopy. The results show that under uniaxial tensile strain, the ISC between two graphene layers evolves sequentially with bonding, sliding and debonding process, and the corresponding interfacial shear strength is inversely proportional to the sample size. Molecular dynamics (MD) simulations demonstrate the origin of this inverse proportionality as stronger interlayer vdW interaction induced by the edge lattices and atoms of BLG that have more degrees of freedom. These results not only provide new fundamental insights into the multiscale interpretation of macroscopic interfacial shear properties of 2D vdW stacks but also have great potential in guiding the design of graphene-based composite materials and flexible 2D electronics.

Structural and electrical properties of sulfur-doped graphene oxide/graphite oxide composite

The sulfur-doped graphene oxide/graphite oxide composite material was synthesized in an original way, and a detailed study of its structural arrangement was carried out using XRD and Raman spectroscopy. Negative differential resistive properties of the obtained material were observed on the current-voltage curve at room temperature as a result of limited proton hopping through water molecules adsorbed on the hydrophilic surface of graphene oxide layers in the presence of a sulfur-enriched graphite oxide component with high electron conductivity, which promotes spatial charge separation and increases the efficiency of H+ transport. The obtained result offers a new way for the one-pot synthesis of new graphene-based composite materials with a wide range of possible applications.

Preparation of zinc oxide graphted nickel incorporated mesoporous SBA-16 doped graphene oxide: An efficient catalyst for transesterification of waste edible oil to biodiesel and photocatalytic degradation of organic dyes

Graphene-based composite materials a wide range of applications, including the production of electronic components and capacitors, as well as adsorption and catalysis. In this work, the ZnO/Ni-SBA-16@GO nanocatalyst was applied to synthesized biodiesel from waste edible oil (WEO) as an efficient and easily available source. The said nanomaterial was applied for the degradation of methylene blue (MB) and methyl orange (MO). The catalyst was characterized by HRTEM, XRD (small angle and wide angle), SEM, EDX, BET, N2 adsorption/desorption isotherm, and TGA. The findings illustrated that the nanostructure has well-controlled pore diameter (4.0 nm) and prominent surface area (735 m2/g). Furthermore, it was possible to reuse the catalyst up to five times; with the results indicating that the catalyst's catalytic activity was sufficient for the synthesis of WEO biodiesel for up to three cycles before diminishing. The present study used a centralized composite approach to look at the influence of numerous features on biodiesel synthesis in order to discover the optimal conditions for biodiesel production. According to the findings, the maximum biodiesel conversion yields 98% had been obtained during a 7-hour reaction time at a temperature of 70 °C. The nanostructure has also been worked as a photocatalyst to degrade MB and MO. According to the statistics, more than 90% of both dyes were degraded in less than 40 min.

Review on Graphene-, Graphene Oxide-, Reduced Graphene Oxide-Based Flexible Composites: From Fabrication to Applications.

In the new era of modern flexible and bendable technology, graphene-based materials have attracted great attention. The excellent electrical, mechanical, and optical properties of graphene as well as the ease of functionalization of its derivates have enabled graphene to become an attractive candidate for the construction of flexible devices. This paper provides a comprehensive review about the most recent progress in the synthesis and applications of graphene-based composites. Composite materials based on graphene, graphene oxide (GO), and reduced graphene oxide (rGO), as well as conducting polymers, metal matrices, carbon–carbon matrices, and natural fibers have potential application in energy-harvesting systems, clean-energy storage devices, and wearable and portable electronics owing to their superior mechanical strength, conductivity, and extraordinary thermal stability. Additionally, the difficulties and challenges in the current development of graphene are summarized and indicated. This review provides a comprehensive and useful database for further innovation of graphene-based composite materials.

Research progress of thermal transport in graphene-based thermal interfacial composite materials

With the rapid increase of the thermal power density of microelectronic devices and circuits, controlling its temperature has become an urgent need for the development and application of the electronic industry. By virtue of the ultrahigh thermal conductivity of graphene, developing high-performance graphene-based composite thermal interface materials has attracted much research attention and become one of hot research topics. The understanding of phonon transport mechanism in graphene-based composites at atomic scale can be helpful to enhance the heat conductive capability of composites systems. In this review, focused on graphene-based thermal interfaces materials, the heat conduction mechanism and the regulating strategy are introduced on both the internal thermal resistance and interfacial thermal resistance. Finally, the reseach progress and opportunities for future studies are also summarized.

A Review on the Production Methods and Applications of Graphene-Based Materials.

Graphene-based materials in the form of fibres, fabrics, films, and composite materials are the most widely investigated research domains because of their remarkable physicochemical and thermomechanical properties. In this era of scientific advancement, graphene has built the foundation of a new horizon of possibilities and received tremendous research focus in several application areas such as aerospace, energy, transportation, healthcare, agriculture, wastewater management, and wearable technology. Although graphene has been found to provide exceptional results in every application field, a massive proportion of research is still underway to configure required parameters to ensure the best possible outcomes from graphene-based materials. Until now, several review articles have been published to summarise the excellence of graphene and its derivatives, which focused mainly on a single application area of graphene. However, no single review is found to comprehensively study most used fabrication processes of graphene-based materials including their diversified and potential application areas. To address this genuine gap and ensure wider support for the upcoming research and investigations of this excellent material, this review aims to provide a snapshot of most used fabrication methods of graphene-based materials in the form of pure and composite fibres, graphene-based composite materials conjugated with polymers, and fibres. This study also provides a clear perspective of large-scale production feasibility and application areas of graphene-based materials in all forms.

One-step synthesis of graphene-based composite phase change materials with high solar-thermal conversion efficiency

Graphene-based composite phase change materials (PCMs) exhibit great potential applications in the field of solar-thermal energy conversion and storage, recently, due to their attracting capability of endowing the PCMs with superior light absorption ability and preventing the liquid phase leakage during the transition process. However, current synthesis methods of graphene-based composite PCMs usually involve complicated multi‐step procedures, greatly hindering its large-scale preparation for the practical application of the solar-thermal energy utilization technique. Herein, we report a facile and straightforward one-step strategy of constructing graphene-based shape-stable composite PCMs with polyethylene glycol (PEG) in situ filled into a graphene oxide (GO) network structure hydrogel. Using this one-step strategy, we achieve a high PEG loading capacity up to 95 wt% in the graphene-based composite PCMs. The composite PCMs also have a relatively constant phase change enthalpy of 162.8 J/g even after 1000 heating–cooling cycles. Most importantly, the composites exhibit a superior solar-thermal conversion ability with the conversion efficiency as high as 93.7%. Compared with the currently reported synthetic routes, the complicated processing steps are greatly reduced in this one-step synthesis strategy. This work proposes a simple and efficient method of synthesizing graphene-based composite PCMs with superior solar-thermal conversion efficiency, which may have great potential applications in the field of solar-thermal energy conversion and storage.

Methods of Synthesis and Specific Properties of Graphene Nano Composites for Biomedical and Related Energy Storage Applications

The concept of graphene in a carbon framework has given rise to enormous improvements to the specific properties of materials. Notably, the combination of graphene with polymeric, metallic and ceramic materials has significantly improved mechanical resistance, electrical and thermal conductivity, and thermal stability of the resulting composite material. In this review, we discuss comprehensive literature on graphene-based composite materials for biomedical and related energy storage applications with emphasis to the synthesis techniques and improved properties of the nanocomposite materials due to graphene addition.

Using Graphene-Based Composite Materials to Boost Anti-Corrosion and Infrared-Stealth Performance of Epoxy Coatings.

Corrosion prevention and infrared (IR) stealth are conflicting goals. While graphene nanosheets (GN) provide an excellent physical barrier against corrosive agent diffusion, thus lowering the permeability of anti-corrosion coatings, they have the side-effect of decreasing IR stealth. In this work, the anti-corrosion properties of 100-μm-thick composite epoxy coatings with various concentrations (0.01–1 wt.%) of GN fillers thermally reduced at different temperatures (300 °C, 700 °C, 1100 °C) are first compared. The performance was characterized by potentiodynamic polarization scanning, electrochemical impedance spectroscopy, water contact angle and salt spray tests. The corrosion resistance for coatings was found to be optimum at a very low filler concentration (0.05 wt.%). The corrosion current density was 4.57 × 10−11 A/cm2 for GN reduced at 1100 °C, showing no degradation after 500 h of salt-spray testing: a significant improvement over the anti-corrosion behavior of epoxy coatings. Further, to suppress the high IR thermal signature of GN and epoxy, Al was added to the optimized composite at different concentrations. The increased IR emissivity due to GN was not only eliminated but was in fact reduced relative to the pure epoxy. These optimized coatings of Al-GN-epoxy not only exhibited greatly reduced IR emissivity but also showed no sign of corrosion after 500 h of salt spray test.

Veterinary antibiotics in soils: Environmental processes, ecotoxicity, and risk mitigation

<p indent=0mm>Concentrated animal feeding operations have long extensively used antibiotics to prevent and treat infectious animal diseases and promote the growth of farmed animals, which have resulted in discharges of large quantities of un-metabolized veterinary antibiotics into agricultural soils along with the land application of animal manure. These veterinary antibiotics in soils could exert a range of ecotoxicological effects and even induce the emergence and development of antimicrobial-resistant microbes and genes, which pose a potential threat to human health. This review provides a systematic overview of the transport and fate processes of antibiotics in the soil environment and the corresponding mechanism, their ecotoxicological effects on crops, soil fauna, and soil microorganisms, and the strategies that can be used to mitigate the risk of antimicrobial pollution and the related mechanism. The major environmental processes of antibiotics in soil, including adsorption/desorption, biodegradation, and abiotic degradation, all strongly depend on the soil’s physical and chemical properties (e.g., pH and organic matter content) and the chemical structures and properties of antibiotics (e.g., functional group and hydrophobicity). The ecotoxicological effects of veterinary antibiotics on crops, soil fauna, and soil microorganisms are mainly determined by their types and concentrations and the soil’s physical and chemical properties. Antibiotic degradation during manure composting and anaerobic digestion primarily occurs through biodegradation and hydrolysis. The antibiotics in manure can be effectively degraded by high-temperature pyrolysis. In addition, biochar and graphene-based composite materials can stabilize the antibiotics in soils through hydrogen bonding, surface complexation, electrostatic interaction, and ion exchange. Important questions that must be addressed and recommendations for future research are proposed herein based on the summary of the recent research progresses on soil pollution by antibiotics.

Facile preparation of graphene/polyaniline composite hydrogel film by electrodeposition for binder-free all-solid-state supercapacitor

The combination of graphene and polyaniline (PANI) as electrodes for supercapacitors has attracted dramatic interests due to their synergistic effects. However, the preparation of the electrode materials usually involves complicated process and other additives. In this work, we report the facile fabrication of the graphene/PANI composite hydrogel film as the symmetric all-solid-state supercapacitor electrode. The free-standing reduced graphene oxide (rGO) hydrogel film is hydrothermally synthesized from a GO solution layer, which is used for subsequent electropolymerization of PANI. The electrochemical measurements of the resulting rGO/PANI hydrogel film present the capacitance of 853.7 F g−1 at 1 A g−1 with good rate capability and cycling stability. In addition, the hydrogel composite film is assembled into the symmetric all-solid-state capacitor without any additives and attains the capacitance of 741.8 F g−1 with a high capacitance retention of 92.6% after 8000 cycles. These excellent electrochemical properties of the composite film are ascribed to the joint effort of superior conductivity and porous structure of rGO matrix with the outstanding pseudocapacitive property of PANI. The convenient method could be considered for the preparation of graphene-based functional composite materials.

3D isotropic hole-in-platelet graphene hydrogels with high surface area and fast mass transfer ability as efficient adsorbents

Abstract Integrating the advantages in adsorption and solving the problems of agglomeration and reclamation of 2D graphene, 3D graphene have been regarded as the idea adsorbents for next generation. Nerveless, the mediocre adsorption capacity and comparatively long adsorption time are the key bottlenecks hindering the practical implementations of graphene monolith. Here, we displayed the rational design of 3D graphene hydrogels with isotropic microstructure and in-platelet holes (3D NGH). The isotropic microstructure induced by reducing the size of graphene oxide (GO) lamellae effectively reduced the overlap ratio of graphene and rendered NGH an desired specific surface area (SSA) of 437.07 m2 g−1. Benefiting from that, NGH exhibited an ultrahigh maximal adsorption capacity of 1120.28 mg g−1, where methylene blue (MB) was chosen as the verifiable pollutant. Meanwhile, the in-platelet holes of NGH obtained by simply HNO3 etching significantly improved the mass transfer ability and adsorption rate of SGH (about a fivefold increase from 2.235 × 10−5 to 12.670 × 10−5 g mg−1 min−1). This facile and scalable preparation tackled the two critical issues of 3D graphene adsorbents simultaneously and laid a valuable groundwork for future development in constructing graphene-based composite materials for environmental or energy applications.

Probing the prediction of effective properties for composite materials

This article presents different micromechanical modelling techniques based on analytical and numerical approaches to determine the effective elastic and piezoelectric (piezoelastic) properties of graphene-based composite materials. Different types, orientations and shapes as well as different geometrical parameters of fiber reinforcement are considered for estimating the effective properties. The effective properties of composite are predicted with and without considering the strong covalent bond which provides interaction and in-plane stability of 2Dcrystalline graphene or strong van der Wall forces formed between graphene layers and the matrix. It is revealed that the axial, transverse and shear effective piezoelastic properties of graphene reinforced piezoelectric composite (GRPC) are significantly enriched due to the incorporation of graphene into the epoxy matrix. The importance of incorporating graphene as nanofillers/interphase into the conventional epoxy matrix to form an advanced composite and its effective properties are illustrated while these results show excellent agreement with previously reported experimental estimates. These results reveal that due to incorporation of graphene nanofillers, there is a significant enhancement in effective properties of composite. The results would also help to recognize the most important material properties with respect to different shapes and orientation of reinforcements which influences the performance of system significantly. To confirm safety, robustness and sustainability of the structure, it is the most prior requirement to determine the effective properties of composites considering different parameters for the different static and structural analyses.