Graphene-based Composites Research Articles

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.

Graphene-Based TiO2 Cement Composites to Enhance the Antibacterial Effect of Self-Disinfecting Surfaces

This paper studies the photocatalytic performance of graphene-based titanium dioxide (TiO2) on cementitious composites for the decomposition of Escherichia coli (E. coli) under visible light. Graphene-based TiO2 was first synthesized through a hydrothermal process. The composites were then evaluated in terms of adsorption capability and degradation of methylene blue dyes. The adsorption test shows a remarkable increase in the amount of dye adsorbed into the composite surface. GO-P25 could adsorb around 60% of the initial dye, while less than 10% of the initial dye was adsorbed by pristine TiO2-P25. The synthesized graphene-based TiO2 significantly enhanced the dye degradation activity (94%) compared to pristine P25 (36%) and Krono (52%), even with the longer irradiation time for P25 and Krono. This led to an increase in reaction rate that was almost 20 times that of P25. Considering the good adsorption capabilities and high photodegradation of dye under visible light for GO-P25, cement-based surfaces containing GO-P25 are expected to be improved for the decomposition of Escherichia coli (E. coli) under visible light. Graphene-based TiO2 on a cement-based surface showed high antibacterial activity with a 77% reduction in number of bacteria compared to a cement-based surface containing pristine TiO2. This study confirms the effectiveness of the composites for disinfection of E. coli under visible light.

Minute-level-fast and recyclable large-area monolayer graphene transfer onto polymer membranes

Monolayer graphene-based composites are of immense importance for research and applications in the microelectronic and thermal-management fields. For the current continuous production of monolayer graphene protocols, chemical etching of the catalyst layer acts as the bottleneck, which is tedious, expensive, and polluting. Thus in this work, by combining chemical etching and mechanical exfoliation, copper foil etching has been compressed from hours to 30 s, with the foil entirely recyclable and reusable. Furthermore, the whole transfer process could be confined within 7 min, including all pre- and post-treatments, without the usage of any intermediate, glue, electricity, vacuum, heat, or pressure. And this minute-level-fast monolayer graphene transfer could be performed continuously multiple times. The key to this novel transfer method is the superficial etching and the subsequent delamination of copper foil off graphene. In-situ OM, AFM, SEM, Raman, and UV–vis spectra have been employed to carefully inspect the transfer mechanism, effectiveness, and quality. The prepared monolayer graphene/polymer composite membrane is ultrathin (∼200 nm), conductive, highly transparent (93.9%), and flexible simultaneously. Its application as an ultrathin, efficient, and conformable Joule heating membrane-form device has been demonstrated. This minute-level-fast transfer is well-adapted to continuous monolayer graphene production and could considerably improve their practicality and efficiency. Additionally, this study provides more understanding of the interface between graphene-polymer and graphene-catalyst and a minute-level-fast route to fabricate 2D-based polymeric composite materials.

Synthesis of nitrogen-doped reduced graphene oxide/magnesium ferrite/polyaniline composite aerogel as a lightweight, broadband and efficient microwave absorber

The fabrication of graphene-based microwave absorbing materials with low density, small filling ratio, broad bandwidth and strong absorption remains a huge challenge. In this work, nitrogen-doped reduced graphene oxide/magnesium ferrite/polyaniline (NRGO/MgFe2O4/PANI) composite aerogel was synthesized by a three-step method of solvothermal reaction, in situ chemical oxidation polymerization and hydrothermal self-assembly. The results showed that the obtained aerogels had a unique three-dimensional (3D) porous network structure and low bulk density (11.1–13.0 mg cm−3). It was worth noting that in the NRGO/MgFe2O4/PANI ternary composite aerogel, MgFe2O4 coated with a thin PANI layer was anchored on the surface of NRGO sheets. Furthermore, the NRGO/MgFe2O4/PANI ternary composite aerogel showed much better microwave absorbing capacity compared with pure NRGO aerogel and NRGO/MgFe2O4 binary composite aerogel. When the filling ratio was as low as 11.5 wt.%, the obtained ternary composite aerogel exhibited the maximum effective absorption bandwidth of 7.0 GHz at a matching thickness of 2.1 mm, and the minimum reflection loss of -42.9 dB at a thickness of 3.57 mm. Additionally, the probable microwave dissipation mechanism was also elucidated. It was believed that this study would pave the way for the construction of 3D graphene-based composites as lightweight, broadband and efficient microwave absorbents.

Advances in new materials for bone tissue engineering simplifying postoperative rehabilitation: Recent Scientific Breakthroughs

Introduction: Bone tissue engineering has emerged as a promising field in regenerative medicine, aiming to develop innovative materials and approaches for bone repair and regeneration, which also leads to the simplification and search for new approaches in postoperative rehabilitation. The integration of novel materials into scaffolds and implants plays a crucial role in improving bone tissue engineering strategies. In recent years, scientific research has made significant progress in identifying and characterizing novel materials with superior properties and functionalities.
 Aim: This article explores the most recent scientific findings and research breakthroughs concerning novel materials for bone tissues, focusing on their biocompatibility, mechanical properties, bioactivity, and potential clinical applications.
 Conclusion: In recent years, the field of bone tissue engineering has witnessed remarkable advancements in the development of novel materials for bone repair and regeneration, which also simplify the medical rehabilitation of the patient. From bioactive glasses and calcium phosphate-based materials to biodegradable magnesium-based materials and graphene-based composites, researchers have explored a wide range of materials with diverse properties and functionalities. As the field continues to evolve, the integration of cutting-edge technologies, such as 3D printing and nanotechnology, is expected to further enhance the efficacy and clinical relevance of these novel materials, ultimately benefiting patients with bone defects and diseases.

Effect of Incorporation of Graphene Nanoplatelets on Physicochemical, Thermal, Rheological, and Mechanical Properties of Biobased and Biodegradable Blends.

This work aimed to study the effect of the incorporation of graphene nanoplatelets (GRA 0.5% and 1% (w/w)) on the matrices of biobased polymers composed of starch-based materials (B20) and poly(butylene succinate) (PBS) using pine rosin (RES) as a compatibilizer. Three formulations were produced (B20/RES/PBS, B20/RES/PBS/GRA0.5%, and B20/RES/PBS/GRA1%), and their mechanical properties (tensile, flexural, hardness, and impact), rheological behavior, thermal properties (thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC)), chemical analysis (Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy), and contact angle were evaluated. Hardness (Shore D), tensile, and flexural moduli increased, whereas elongation at break and toughness decreased as GRA content increased. FTIR studies strongly supported the existence of interactions between polymeric matrices and the large surface area of GRA. The viscosity flow curves were well fitted to the Cross-Williams-Landel-Ferry (Cross-WLF) model, and the three formulations exhibited non-Newtonian (shear-thinning) behavior. The analysis of water contact angles indicated that the formulation surfaces have hydrophilic behavior. All the samples are thermally stable, and the results of this study can be used to optimize the application of biobased graphene-based composites for applications in injection molding industries.

Three-dimensional rGO/CNT/g-C3N4 macro discs as an efficient peroxymonosulfate activator for catalytic degradation of sulfamethoxazole

Over the past few years, advanced oxidation processes (AOPs) have shown promising efficiencies for wastewater remediation. Carbocatalysis, in particular, has been exploited widely thanks to its sustainable and economical properties but has an issue of recovery and reusability of the catalysts. To address this, three-dimensional (3D) binary and ternary graphene-based composites in the form of macro discs were created to activate peroxymonosulfate (PMS) for catalytic oxidation of sulfamethoxazole (SMX). Graphene oxide served as the base, while graphitic carbon nitride (g-C3N4) and/or single-walled carbon nanotubes (SWCNTs) were added. Among the various discs synthesized, rGNTCN discs (ternary composite) were proven to be the most efficient by completely degrading SMX in 60 min owing to their large surface area and nitrogen loading. The catalytic system was further optimized by varying the reaction parameters, and selective radical quenching and electron paramagnetic resonance tests were performed to identify the active radical, revealing the synergistic role of both radical and non-radical pathways. This led to the development of possible SMX degradation pathways. This research not only provides insights into ternary carbocatalysis but also gives a novel breakthrough in catalyst recovery and reusability by transforming nanocatalysts into macro catalysts.

Can Graphene Pave the Way to Successful Periodontal and Dental Prosthetic Treatments? A Narrative Review.

Graphene, as a promising material, holds the potential to significantly enhance the field of dental practices. Incorporating graphene into dental materials imparts enhanced strength and durability, while graphene-based nanocomposites offer the prospect of innovative solutions such as antimicrobial dental implants or scaffolds. Ongoing research into graphene-based dental adhesives and composites also suggests their capacity to improve the quality and reliability of dental restorations. This narrative review aims to provide an up-to-date overview of the application of graphene derivatives in the dental domain, with a particular focus on their application in prosthodontics and periodontics. It is important to acknowledge that further research and development are imperative to fully explore the potential of graphene and ensure its safe use in dental practices.

Effect of the Addition of Graphene Flakes on the Physical and Biological Properties of Composite Paints.

In this study, graphene flakes were obtained using an electrolytic method and characterized using X-ray diffraction (XRD), Raman and FTIR spectroscopy, scanning and transmission electron microscopy (SEM/TEM). Graphene-based composites with varying concentrations of 0.5%, 1% and 3% by weight were prepared with acrylic paint, enamel and varnish matrices. The mechanical properties were evaluated using micro-hardness testing, while wettability and antimicrobial activity against three pathogens (Staphylococcus aureus 33591, Pseudomonas aeruginosa 15442, Candida albicans 10231) were also examined. The results indicate that the addition of graphene flakes significantly enhances both the mechanical and antimicrobial properties of the coatings.

Toward Sustainable Composites: Graphene-Modified Jute Fiber Composites with Bio-Based Epoxy Resin.

Sustainable natural fiber reinforced composites have attracted significant interest due to the growing environmental concerns with conventional synthetic fiber as well as petroleum-based resins. One promising approach to reducing the large carbon footprint of petroleum-based resins is the use of bio-based thermoset resins. However, current fiber-reinforced bio-based epoxy composites exhibit relatively lower mechanical properties such as tensile, flexural strength, and modulus, which limits their wider application. Here the fabrication of high-performance composites using jute fibers is reported, modified with graphene nanoplates (GNP) and graphene oxide (GO), and reinforced with bio-based epoxy resin. It is demonstrated that physical and chemical treatments of jute fibers significantly improve their fiber volume fraction (Vf) and matrix adhesion, leading to enhanced mechanical properties of the resulting Jute/Bio-epoxy (J/BE) composites. Furthermore, the incorporation of GNP and GO further increases the tensile and flexural strength of the J/BE composites. The study reveals the potential of graphene-based jute fiber-reinforced composites with bio-based epoxy resin as a sustainable and high-performance material for a wide range of applications. This work contributes to the development of sustainable composites that have the potential to reduce the negative environmental impact of conventional materials while also offering improved mechanical properties.

Effects on the Microstructure Evolution and Properties of Graphene/Copper Composite during Rolling Process.

Rolling treatments have been identified as a promising fabrication and deformation processing technique for graphene/metal composites with high performance. However, it is still a challenge to choose appropriate rolling parameters to achieve high strength, ductility and electrical conductivity of the composite simultaneously. In this study, graphene/Cu composites were prepared with an in situ growth method and rolling treatment. The effects of rolling deformation and temperature on the microstructural evolution of graphene and Cu grains, interface bonding between graphene and the matrix, mechanical and electrical properties were systemically investigated. The cold-rolled composite with 85% deformation displayed a maximum ultimate strength of 548 MPa, a high elongation of 8.8% and a good electrical conductivity of 86.2% IACS. This is attributed to oriented graphene arrangement and matrix grain refinement. Our research provides a comprehensive understanding for the rolling behavior of graphene/Cu composites, and can promote the development of graphene-based composites with high performance.

Fabrication of nitrogen-doped reduced graphene oxide/porous magnesium ferrite@silica dioxide composite with excellent dual-band electromagnetic absorption performance

In order to solve the increasingly serious problem of electromagnetic radiation pollution, it is urgent to develop advanced electromagnetic wave (EMW) absorbers with low filling ratio, wide bandwidth and strong absorption. In this work, nitrogen-doped reduced graphene oxide/porous magnesium ferrite@silicon dioxide (NRGO/MgFe2O4@SiO2) composite was prepared by a three-step route of solvothermal reaction, Stöber method and hydrothermal synthesis. The results of microscopic morphology analysis showed that a large number of MgFe2O4@SiO2 core–shell microspheres were uniformly distributed on the wrinkled surface of NRGO in the ternary composite. Furthermore, the effect of dielectric SiO2 coating on the electromagnetic parameters and EMW absorption performance of NRGO/MgFe2O4 composite was also investigated. Significantly, the EMW absorption capacity of the obtained ternary composite was better than that of the other two binary composites. When the filling ratio was 20.0 wt.% and the matching thickness was 2.0 mm, the ternary composite exhibited the widest absorption bandwidth of 6.2 GHz and the strong absorption strength of -58.8 dB at 14.6 GHz (Ku band). It was worth noting that when the thickness was increased to 4.2 mm, the optimal reflection loss of -61.0 dB was achieved at 5.8 GHz (C band). In addition, the potential EMW absorption mechanism was also proposed. Therefore, this work would provide a valuable reference for the preparation of graphene-based magnetic composites as lightweight, broadband and efficient EMW absorbers.

Enhanced Electrical and Thermal Conductivities of Polymer Composites with a Segregated Network of Graphene Nanoplatelets.

Introducing a segregated network constructed through the selective localization of small amounts of fillers can be a solution to overcome the limitations of the practical use of graphene-based conductive composites due to the high cost of fillers. In this study, polypropylene composites filled with randomly dispersed GNPs and a segregated GNP network were prepared, and their conductive properties were investigated according to the formation of the segregated structure. Due to the GNP clusters induced by the segregated structure, the electrical percolation threshold was 2.9 wt% lower than that of the composite incorporating randomly dispersed GNPs. The fully interconnected GNP cluster network inside the composite contributed to achieving the thermal conductivity of 4.05 W/m∙K at 10 wt% filler content. Therefore, the introduction of a segregated filler network was suitable to simultaneously achieve excellent electrical and thermal conductivities at a low content of GNPs.

Ultrasensitive electrochemical detection of glyphosate using crumpled graphene/copper oxide nanocomposite

Glyphosate (Glyp) is an herbicide mainly employed worldwide. This has generated significant concern regarding the toxicological impacts and risks to humans, primarily water contamination. Therefore, the monitoring of glyphosate in water is demanding. Herein, we synthesized in one step crumpled graphene fully decorated with copper oxide nanoparticles (CG/CuO) for ultrasensitive electrochemical detections of glyphosate in water. The linear range was obtained by differential pulse voltammetry and performed in picomolar (5.00 – 25.00 ×10-12 M), demonstrating exceptional linearity, with limits of detection - LD (0.30 ×10-12 M) and quantification - LQ (0.90 ×10-12 M). Furthermore, the successful recovery analysis of enriched glyphosate from the distilled-deionized, river, groundwater, and untreated tap water, with great accuracy and precision achieved at low concentrations, demonstrated the advantages of our CG/CuO electrochemical sensor. This one-step strategy to prepare crumpled graphene-based copper composites is a promising method for future in-loco detection of Glyp.

Effects of Graphene-Based Metal Composite and Urea on Seed Germination and Performance of Berberis chitria Buch.-Ham. ex Lindl.

Being an important source of berberine, Berberis chitria Buch.-Ham. ex Lindl. (Berberidaceae) has high demand in pharmaceutical industries. Its populations are diminishing due to overexploitation, habitat loss, slow-growing nature, and climate change. It is important to develop propagation protocols to sustain its natural populations and ensure its survival in the future. Fertilizers play an essential role in the yield and productivity of different crops. Among others, urea is the most abundantly used fertilizer in crops. Its effects on the yield and survival of medicinal plants are poorly studied. However, it is known that applying urea for a long time affects the soil negatively. Due to these negative effects, alternative fertilizers such as graphene-based metal composite (GMC) are being tested for their efficiency. In the present study, for the first time, we tested the effects of urea and GMC on the germination and performance of B. chitria. GMC showed maximum germination at 30ppm (75%) and urea at 15ppm (79%). Findings reveal non-significant effects of GMC and urea on germination and performance of B. chitria, suggesting the use of GMC as an alternative fertilizer.

Large-Scale Molecular Dynamics Elucidates the Mechanics of Reinforcement in Graphene-Based Composites.

Using very large-scale classical molecular dynamics, the mechanics of nano-reinforcement of graphene-based nanocomposites are examined. Simulations show that significant quantities of large, defect-free, and predominantly flat graphene flakes are required for successful enhancement of materials properties in excellent agreement with experimental and proposed continuum shear-lag theories. The critical lengths for enhancement are approximately 500 nm for graphene and 300 nm and for graphene oxide (GO). The reduction of Young's modulus in GO results in a much smaller enhancement of the composite's Young's modulus. The simulations reveal that the flakes should be aligned and planar for optimal reinforcement. Undulations substantially degrade the enhancement of materials properties.

Layer-By-Layer (LBL) hybrid MOF coating for graphene-based multilayer composite: Synthesis and application as anode for lithium ion batteries

The hybrid anodic materials with high porosity and low charge resistance exhibit high specific capacity and stable cyclic stability for lithium ion battery (LIBs). For this purpose, three-dimensional hollow material, metal organic framework (MOF-199) was coated over the active surface of oxidized derivative of graphene (Graphene oxide, GO), via layer-by-layer (LBL) coating method. Cupric acetate and benzene-1,3,5-tricarboxylic acid [Cu3(BTC)2], were alternatively coated on the active surface of GO as an anode material, to enhance the structural diversity and reduce the synergistic effect of insertion and extraction of Li+ ions for LIBs. Sharp absorption peaks from 1620 cm−1 to 1360 cm−1 and intense ring bends ∼1000 cm−1 was identified through FTIR. Powder XRD provides the evidence for size reduction of Cu3(BTC)2@GO composite (32.6 nm) comparative to GO (43.7 nm). Outcome of EIS analysis shows the charge transfer resistance of simple GO is 2410 Ω, which is 4 times higher than Rct of Cu3(BTC)2@GO composite (590 Ω). Similarly the Warburg impedance co-efficient for simple GO (448.8 Ωs−1/2) is also higher than Aw of Cu3(BTC)2@GO composite (77.64 Ωs−1/2). The synthesized material show high initial charge/discharge capacity, 1200/1420 mAh/g with 85% Coulombic efficiency and reversible discharge capacity, 1296 mAh/g after 100 cycles at 100 mA/g current density. The 98.9% Coulombic efficiency and 91% retaining capacity of composite at 100th cycle with cyclic stability, provides the phenomenon approach towards the rechargeable LIBs for industrial technology.

Investigation of low-percentage graphene reinforcement on the mechanical behaviour of additively manufactured polyethylene terephthalate glycol composites

The current work investigates the influence of graphene on the mechanical properties of additive-manufactured polyethylene terephthalate glycol (Prince Edward IslandTG) composites. To this end, the graphene content is varied by 0.02 wt.%, 0.04 wt.%, 0.08 wt.%, and 0.1 wt.% to obtain different compositions of PETG/graphene composites. The filaments were prepared by mixing the PETG pellets and graphene flakes into the required quantity. Further, the mixture is extruded using a single screw extruder into small filaments with a 1.75 mm diameter. Using fused deposition modelling (FDM), the specimens were 3D printed following ASTM requirements. The fabricated PETG/graphene specimens are assessed for their mechanical properties, such as tensile, compression, flexural and impact characteristics. Finally, the fractography of the tested specimens is analysed using a scanning electron microscope (SEM). The experimentation of PETG/graphene composites reveals that the optimum mechanical properties can be achieved when PETG is reinforced with 0.04 wt.% of graphene. As opposed to virgin PETG, an increment of 89.71%, 81.76%, 21.60%, and 81.25% is witnessed in the tensile, compression, flexural, and impact strengths of the PETG/0.04 wt.% graphene composite. The outcome of this work is believed to pave the way for broadening the applications of graphene-based composites in electromechanical and smart structure engineering domains.

Surface free energy of graphene-based coatings and its component elements

There has been an increase in research into the surface free energy of low-dimensional materials in recent years. Graphene-based composites are increasingly popular in industry as coating materials. The surface free energy of graphene is crucial for interfacial adherence to supporting substrates. In this article, the surface free energy of coatings made of graphite base, graphene, and graphene oxide is evaluated critically based on the provided contact angle data using a variety of techniques, such as the Zisman, Neumann, Fowkes, Owens-Wendt-Fowkes, and van Oss, Chaudhury, Good method. It was found that the average surface energies of graphene, graphene oxide, and graphite were respectively 44.8 ± 14.7, 47.9 ± 7.2, and 53.6 ± 2.1 mJ.m-2. The dispersive components of graphene, graphene oxide, and graphite are 38.4 ± 9.5, 38.3 ± 4.0, and 50.6 ± 3.6 mJ.m-2, respectively, while the polar components are 4.8 ± 4.9, 9.9 ± 4.2, and 2.8 ± 1.5 mJ.m-2. The current analysis can be used to develop graphene-based composites for the coatings sector.

Revealing promotion of interfacial Pt–O–Fe oxygen bridge structure in PtFe/graphene synthesized by a four-electrode electrochemical system on water splitting

To promote kinetic rate of half reactions in water splitting, we synthesized a bifunctional PtFe/graphene with dual active sites by a facile self-designed four-electrode electrochemical method. Characterization data indicate interfacial oxygen bridge structure of Pt–O–Fe is expectedly formed and electrons transfer from Fe to Pt via this bridge structure. This unique interfacial structure not only regulates electronic structure of Pt and Fe, but also offers interfacial electron-transfer channel to improve overall conductivity, which essentially enhances intrinsic activity towards acidic HER and alkaline OER. For HER, the best Pt–Fe/G shows the mass activity of 4239.3 mA mg−1 at −0.063 V, 3.79 times higher than that of Pt/G (1118.5 mA mg−1) and 5.02 times higher than that of commercial Pt/C (843.1 mA mg−1) catalyst, respectively. Introduction of Fe to Pt decreases the energy barrier of HER process (ΔG∗), and results in conversion of rate-limiting step from H+ adsorption (Volmer step) to H∗ desorption (Tafel step). For OER, the greatest PtFe/G exhibits an overpotential of lower 26 mV (10 mA cm-2) than commercial RuO2 and its mass activity is 16.7 times higher than Fe/G. The formed Pt–O–Fe bond effectively elevates the electrophilic properties and facilitates adsorption of OH−, contributing to the change of rate-limiting step and enormous decrease of reaction activation energy (Ea). This work inspires researchers to construct efficient interfacial oxygen bridge structure to enhance electrocatalytic performance for water splitting and design novel electrochemical method for synthesis of graphene-based composites.