Graphene-based Composites 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.

Recent research progress and prospect of graphene-based microwave absorbing materials

With the increasing use of electronic devices, electromagnetic wave pollution has become a hot topic of concern and discussion, and microwave absorption materials play an important role in civil and defense military fields. Therefore, the development of electromagnetic wave absorption materials with low density, thin thickness, wide effective bandwidth, and strong wave absorption performance has become the focus and goal of researchers. Graphene shows a unique two-dimensional structure, lightweight, large specific surface area, high electrical conductivity, and high thermal conductivity, which make it a promising electromagnetic wave-absorbing material. However, pure graphene material cannot meet the needs of practical applications due to bad impedance matching. Therefore, graphene is usually combined with other materials (such as carbon materials, magnetic metal, polymer, ferrite, and ceramic) to improve its wave absorption properties. In this review, we summarize recent research progress of different types of graphene-based microwave absorbing materials. In addition, the challenges and prospects for improving the microwave absorption properties of graphene-based composites are presented, which will be useful for those working in related fields.

Highly Reactive Graphene Dispersant and Its Effective Reinforcement for Phase Change Coatings.

High efficient dispersant that meanwhile possesses additional functions is highly desirable for the fabrication of graphene-based composite. In this paper, a new reactive dispersant, multi-silanols grafted naphthalenediamine (MSiND), is synthesized, which shows superiority compared with conventional dispersants. It can not only stabilize graphene in water at a high concentration of up to 16mgmL-1, but also simultaneously be applicable for ethanol medium, in which the graphene concentration can be as high as 12mgmL-1 at the weight ratio of 1:1 (MSiND:graphene). The dispersion is compatible with multi-matrixes and affinity to various substrates. In addition, MSiND exhibits excellent reactivity due to the existence of high-density silanol groups. Tough graphene coatings are constructed on glass slides and non-woven fabric simply by direct painting and dip-coating. Moreover, with the assistance of MSiND, graphene-doped phase-change coatings on hydrophobic non-woven fabric (e.g., functional mask) are prepared via the spray method. The composite coatings show enhanced mechanical strength and excellent energy storage performance, exhibiting great potential in heat preservation and thermotherapy.

Engineering Bacterial Biofilm Development and Structure via Regulation of Silver Nanoparticle Density in Graphene Oxide Composite Coating.

Graphene-based composites have shown significant potential in the treatment of biofilm infections in clinical settings due to their exceptional antimicrobial properties and specific mechanisms. Nevertheless, a comprehensive understanding of the influence exerted by nanoparticles embedded in the composites on the development and structure of biofilms is still lacking. Here, we fabricate different graphene oxide-silver nanoparticle (GAg) composite-modified substrates (GAgS) with varying densities of silver nanoparticles (AgNPs) and investigate their effects on planktonic bacterial adhesion, subsequent biofilm formation, and mature biofilm structure. Our findings indicate that the initial attachment of Pseudomonas aeruginosa cells during biofilm formation is determined by the density of AgNPs on the GAgS surface. In contrast, the subsequent transition from adherent bacteria to the biofilm is determined by GAgS's synergistic antimicrobial effect. There exists a threshold for the inhibitory performance of GAgS, where the 20 μg/cm2 GAg composite completely prevents biofilm formation; below this concentration, GAgS delays the development of the biofilm and causes structural changes in the mature biofilm with enhanced bacterial growth and increased production of extracellular polymeric substance. More importantly, GAgS have minimal impact on mammalian cell morphology and proliferation while not inducing hemolysis in red blood cells. These results suggest that GAg composites hold promise as a therapeutic approach for addressing medical devices and implant-associated biofilm infections.

Fabrication of graphene-based magnetic carbon composites derived from iron cobalt metal-organic framework as dual-band electromagnetic wave absorbers

The fabrication of advanced magnetic carbon electromagnetic wave (EMW) absorbers derived from metal-organic framework (MOF) with thin thickness, wide bandwidth, strong absorption strength and low filling ratio remains a huge challenge. In this paper, CoFe2O4/CoFe/C/Graphene composites were prepared by a simple two-step way of solvothermal reaction and carbonization treatment. The results of micromorphology analysis revealed that as the carbonization temperature increased, the obtained carbon frameworks changed from a spindle shape to dodecahedron-like shape and finally to a tile shape, and the carbonization temperature had a notable influence on the electromagnetic parameters and EMW absorption properties of the magnetic carbon composites. It should be noted that the obtained CoFe2O4/CoFe/C/Graphene composites exhibited comprehensive excellent EMW absorption performance when the carbonization temperature was 750.0 ℃ and the filling radio was only 15.0 wt%, namely the effective absorption bandwidth reached up to 4.8 GHz and the optimal minimum reflection loss was −40.2 dB at a thickness of 2.06 mm. A distinct dual-band (C band and Ku band) absorption feature was observed when the thickness exceeded or equaled 4.5 mm. Furthermore, the underlying electromagnetic dissipation mechanisms were also elucidated. Therefore, our results could provide a valuable reference for preparing excellent magnetic carbon EMW absorbers derived from MOF.

Achieving balanced properties in graphene/Cu composite with oriented bimodal grains: Strength, ductility, and conductivity

In the pursuit of advanced materials with multifunctional capabilities, graphene-based composites have gained substantial attention due to their exceptional mechanical, electrical properties, etc. In this paper, we present a straightforward method for fabricating graphene/Cu composites with an oriented bimodal structure through an in-situ synthesis process combined with hot rolling. Dendritic copper powder, mechanical exfoliation graphene and polyacrylonitrile were used as the raw materials. The graphene/Cu composite with oriented bimodal grains achieves a good balance between strength, ductility and electrical conductivity. Both the fine grains arising from the raised fine particles of dendritic copper powder and the graphene coated on the surface of fine grains facilitate the load transfer, resulting in improved strength of the composites. Furthermore, the formation of coarse grains during sintering and hot rolling deformation contributes to enhanced ductility. Simultaneously, the oriented structure of these coarse grains and graphene sheets establishes an efficient charge transport pathway, ensuring high electrical conductivity. The tensile yield strength of the oriented bimodal composite measures 315 MPa with 0.073 wt% carbon content, while its fracture elongation is 12.4%, and the electrical conductivity remains at 95.7% IACS. This study not only sheds light on the synergistic effects between graphene and copper in a bimodal composite system but also introduces a methodology for tailoring the microstructure to achieve a desired balance between mechanical strength, ductility, and electrical conductivity.

Solution blending preparation of polyurethane/graphene composite: Improving the mechanical and anti-corrosive properties of the coating on aluminum surface

Graphene-based polyurethane composites (PU/G) are prepared by a simple solution blending method to disperse defect-free graphene flakes (prepared via liquid phase exfoliation process) into the polyurethane matrix. The PU/G composite with 1 wt% of graphene flakes performs the significant improvement (∼50 %) of the impact strength (124 kg.cm) and adhesion behavior (∼2.3 MPa) with respect to that of pristine PU. The PU/G coating with 2 wt% of graphene achieves the highest long-term anti-corrosion performance after 150 immersed days in 3 wt% NaCl solution (with the stable impedance modulus of ∼2.7 × 1010 Ω.cm2) or after 2500 h of salt spray exposure in 5 wt% NaCl solution (no corrosive traces detected on aluminum substrate).

Recent advances in the environmental application of graphene-based composites

Graphene-based composites have been widely applied in environmental remediation owing to their high removal capacity.

Recent advances in nitrogen-doped graphene-based heterostructures and composites: mechanism and active sites for electrochemical ORR and HER

Role of different strategies in improving active sites of N-doped graphene based electrocatalysts for sustainable energy.

Tailoring electrochemically exfoliated graphene electroactive pathways in cementitious composites for structural health monitoring of constructions.

Manipulating and exerting a nanoscale control over the structure of multicomponent materials represents a powerful strategy for tailoring multifunctional composites for structural health monitoring applications. The use of self-sensing, electroactive cementitious composites in large-scale applications is severely hindered by the absence of clear directives and a thorough understanding of the electrical conduction mechanisms taking place within the cement matrix. Here we report on a nanoscale approach towards this goal which is accomplished via the development of a novel, multifunctional cementitious composite incorporating electrochemically exfoliated graphene (EEG). The use of commercially available poly(carboxylate ether)-based superplasticizer allowed us to embed in the cement mortar up to 0.8 wt% of EEG which is fully dispersed in the matrix. The multiscale investigation made it possible to assess the effect of such high dosages of EEG on the mechanical performance and hydration degree of cementitious composites. We used electrochemical impedance spectroscopy to monitor the formation of electroactive EEG-based percolation paths for charge transfer within cement mortar, the latter displaying resistivities of 2.67 kΩ cm as well as EEG-cement-EEG capacitive paths with capacitance of 2.20 × 10-10 F cm-1 for composites incorporating 0.6 wt% of EEG. Noteworthy, we have proposed here for the first time an electrical equivalent circuit for the impedance spectroscopy analysis of cementitious composites with high loadings of graphene, exceeding the percolation threshold. These findings underscore the potential of nanoscale structures for civil engineering applications and more specifically may open new avenues for the technological application of graphene-based cementitious composites in self-sensing structures.

Graphene-based Polymer Composites in Thermal Management: Materials, Structures and Applications

Graphene, with its high thermal conductivity (k), excellent mechanical properties, and thermal stability, is an ideal filler for developing advanced high k and heat dissipation materials. However, creating graphene-based polymer...

Progress in materials for 3D printing

The realm of 3D printing is rapidly evolving, offering a wide range of options from typical thermoplastics to advanced graphene-based composites. This technology improves production efficiency and gives consumers more control over customizing products and specifications. However, alongside its transformative potential, 3D printing also presents challenges, such as potential impacts on manufacturing jobs and security issues. Since its modest beginnings in developing visualization models, 3D printing has evolved to transform the manufacturing of distinct devices, implants, tissue engineering scaffolds, and drug delivery systems. This paper explores the most recent progress in 3D printing materials, including smart materials, ceramics, electronics, biomaterials, and composites, emphasizing the significance of adapting to changing materials and product requirements. It delves into the complex connection between printing parameters and the characteristics of printed composite parts, providing new opportunities to improve the strength and functionality of 3D-printed components. This review highlights how 3D printing can be utilized in various industries, such as medical devices and explosives research, using materials such as titanium, aluminum, carbon fiber, and thermoplastic polyurethanes. With the continuous growth of the 3D printing field, it is essential to adopt new methods and materials to fully realize its impact on the future of manufacturing and product development.

Self-powered graphene-based composites for rain energy harvesting

Self-powered graphene-based composites for rain energy harvesting

Engineering of graphene-based composites with hexagonal boron nitride and PEDOT:PSS for sensing applications.

A unique nanomaterial has been developed for sweat analysis, including glucose level monitoring. Simple resusable low-cost sensors from composite materials based on graphene, hexagonal boron nitride, and conductive PEDOT:PSS (poly(3,4-ethylenedioxythiophene)polystyrene sulfonate) polymer have been developed and fabricated via 2D printing on flexible substrates. The sensors were tested as biosensors using different water-based solutions. A strong increase in the current response (several orders of magnitude) was observed for aqua vapors or glucose solution vapors. This property is associated with the sorption capacity of graphene synthesized in a volume of plasma jets and thus having many active centers on the surface. The structure and properties of graphene synthesized in a plasma are different from those of graphene created by other methods. As a result, the current response for a wearable sensor is 3-5 orders of magnitude higher for the reference blood glucose concentration range of 4-14 mM. It has been found that the most promising sensor with the highest response was fabricated based on the graphene:PEDOT:PSS composite. The graphene:h-BN:PEDOT:PSS (h-BN is hexagonal boron nitride) sensors demonstrated a longer response and the highest response after the functionalization of the sensors with a glucose oxidase enzyme. The reusable wearable graphene:PEDOT:PSS glucose sensors on a paper substrate demonstrated a current response of 10-10 to 10-5 A for an operating voltage of 0.5 V and glucose range of 4-10 mM.

Graphene-based phononic crystal lenses: Machine learning-assisted analysis and design

The advance of artificial intelligence and graphene-based composites brings new vitality into the conventional design of acoustic lenses which suffers from high computation cost and difficulties in achieving precise desired refractive indices. This paper presents an efficient and accurate design methodology for graphene-based gradient-index phononic crystal (GGPC) lenses by combing theoretical formulations and machine learning methods. The GGPC lenses consist of two-dimensional phononic crystals possessing square unit cells with graphene-based composite inclusions. The plane wave expansion method is exploited to obtain the dispersion relations of elastic waves in the structures and then establish the data sets of the effective refractive indices in structures with different volume fractions of graphene fillers in composite materials and filling fractions of inclusions. Based on the database established by the theoretical formulation, genetic programming, a superior machine learning algorithm, is introduced to generate explicit mathematical expressions to predict the effective refractive indices under different structural information. The design of GGPC lenses is conducted with the assistance of the machine learning prediction model, and it will be illustrated by several typical design examples. The proposed design method offers high efficiency, accuracy as well as the ability to achieve inverse design of GGPC lenses, thus significantly facilitating the development of novel phononic crystal lenses and acoustic energy focusing.

Graphene-Based Composites for Thermoelectric Applications at Room Temperature

The thermoelectric materials that operate at room temperature represent a scientific challenge in finding chemical compositions with three optimized, independent parameters, namely electrical and thermal conductivity and the Seebeck coefficient. Here, we explore the concept of the formation of hybrid composites between carbon-based materials and oxides, with the aim of modifying their thermoelectric performance at room temperature. Two types of commercially available graphene-based materials are selected: N-containing reduced graphene oxide (NrGO) and expanded graphite (ExGr). Although the NrGO displays the lowest thermal conductivity at room temperature, the ExGr is characterized by the lowest electrical resistivity and a negative Seebeck coefficient. As oxides, we choose two perspective thermoelectric materials: p-type Ca3Co4O9 and n-type Zn0.995Al0.005O. The hybrid composites were prepared by mechanical milling, followed by a pelleting. The thermoelectric efficiency was evaluated on the basis of its measured electrical resistivity, Seebeck coefficient and thermal conductivity at room temperature. It was found that that 2 wt.% of ExGr or NrGO leads to an enhancement of the thermoelectric activity of Ca3Co4O9, while, for Zn0.995Al0.005O, the amount of ExGr varies between 5 and 20 wt.%. The effect of the composites’ morphology on the thermoelectric properties is discussed on the basis of SEM/EDS experiments.

Controlling the Formation of Electroactive Graphene-Based Cementitious Composites: Towards Structural Health Monitoring of Civil Structures.

The development of composites combining multiple components each one imparting a specific function to the ensemble is highly sought after for disruptive applications in chemistry and materials science, with a particular importance for the realization of smart structures. Here, we report on the development of an unprecedented multifunctional cementitious composite incorporating reduced graphene oxide (rGO). By design, this material features significantly enhanced electrical properties while retaining the excellent cement's hydration and microstructure. The multiscale investigation on the chemical and physical properties of the dispersion made it possible to establish an efficient preparation protocol for rGO aqueous dispersion as well as rGO-based cementitious composites using a commercial poly(carboxylate ether)-based superplasticizer. The conduction mechanisms within the matrix of rGO containing mortars were unraveled by electrochemical impedance spectroscopy revealing conductive paths originating from bulk cement matrix and rGO nanosheets in composites with rGO loadings as low as 0.075 wt. %. For this rGO loading, we observed the reduction of the resistivity of bulk cement mortar layers from 18.3 MΩ cm to 2.8 MΩ cm. Moreover, the addition of 0.2 wt. % of rGO resulted in the formation of rGO conductive paths with the resistivity of 51.1 kΩ cm. These findings represent a major step forward towards the practical application of graphene-based materials in structural health monitoring of concrete structures.

Graphene-Based Composites for Biomedical Applications: Surface Modification for Enhanced Antimicrobial Activity and Biocompatibility.

The application of graphene-based materials in medicine has led to significant technological breakthroughs. The remarkable properties of these carbon materials and their potential for functionalization with various molecules and compounds make them highly attractive for numerous medical applications. To enhance their functionality and applicability, extensive research has been conducted on surface modification of graphene (GN) and its derivatives, including modifications with antimicrobials, metals, polymers, and natural compounds. This review aims to discuss recent and relevant studies related to advancements in the formulation of graphene composites, addressing their antimicrobial and/or antibiofilm properties and evaluating their biocompatibility, with a primary focus on their biomedical applications. It was concluded that GN surface modification, particularly with compounds intrinsically active against bacteria (e.g., antimicrobial peptides, silver and copper nanomaterials, and chitosan), has resulted in biomaterials with improved antimicrobial performance. Furthermore, the association of GN materials with non-natural polymers provides composites with increased biocompatibility when interfaced with human tissues, although with slightly lower antimicrobial efficacy. However, it is crucial to highlight that while modified GN materials hold huge potential, their widespread use in the medical field is still undergoing research and development. Comprehensive studies on safety, long-term effects, and stability are essential before their adoption in real-world medical scenarios.

Universal self-assembly of graphene-based composites as free-standing hierarchical electrodes for high-performance aqueous hybrid capacitors

For the development of aqueous hybrid capacitors, it is essential to fulfill the role of active materials and concentrate on the device's performance. However, these goals are challenging because the conventional electrodes meet a heterogeneous distribution of active materials and large-portion passive components. We develop a universal method to prepare free-standing hierarchical graphene-based composited electrodes here. Compared to conventional electrodes, this hierarchical electrode can distribute active materials effectively, improve ion diffusion, increase charge transfer, reduce parasitic reactions, decrease passive components, etc., which facilitates fulfilling the role of active materials and increases the device performance. Typically, the hierarchical electrodes show higher capacity for Fe3O4, NiCo-LDH, PANI, and active carbon. In addition, the hierarchical electrodes can generate a high energy density of 43.7 Wh kg−1 (based on the whole electrodes instead of active materials). Also, the preparation method of hierarchical electrodes is facile, energy-saving, eco-friendly, etc., facilitating the practical application. Such a universal preparation method and high electrochemical performance hold great potential for developing high-performance energy storage devices.

An innovative graphene-based phase change composite constructed by syneresis with high thermal conductivity for efficient solar-thermal conversion and storage

Graphene-based phase change composites hold significant potential for solar energy utilization, but their poor thermal conductivity hinders their practical applications. In this work, an air-dried graphene skeleton (AGS) with excellent thermal conductivity enhancement efficiency was constructed by the ice templating method and syneresis, and the air-dried graphene phase change composite (AGP) was subsequently obtained through vacuum-impregnating n-Docosane (C22) into AGS. The syneresis effectively reduced the phonon scattering between graphene sheets within AGS and increased the density of AGS to 0.1701 g/cm³. Therefore, with a graphene skeleton loading of 23.82 wt.%, AGP exhibited excellent thermal conductivity of 9.867 W/(m K), outstanding electrical conductivity of 68.08 S/cm, and remarkable shape stability. Additionally, AGP demonstrated a melting enthalpy of 188.5 J/g and an outstanding solar-thermal conversion efficiency of 93.98%, showing enormous potential for the utilization of solar energy.