Graphene-based Composites Research Articles

Plasticization stretching strategy towards high strength nacre-like graphene-based composites

Introducing graphene into polymers is a common method to prepare nacre-like functional composites with enhanced mechanical strength and conductive properties. However, the soft nature of graphene sheets makes it easy to form chaotic wrinkles and degrade the mechanical performance of the composites by hindering interlayer stress transfer. Here, we use a simple plasticization and stretching method to flatten the sheet wrinkles and obtain a highly oriented and crystalline graphene-based nacre-like composite film. The composite film shows excellent mechanical properties (tensile strength of 709.2 MPa, toughness of 11.1 MJ m-3), as well as high electrical conductivity of 7671 S m-1, which are much higher than those of as-prepared films without plasticization and stretching. This low cost and facile method opens an avenue to prepare graphene and other 2D nanosheet based composites with enhanced performance.

Self-assembly sandwich-like Fe, Co, or Ni nanoparticles/reduced graphene oxide composites with excellent microwave absorption performance

The application of graphene-based composites as microwave absorbing materials still has some problems despite optimistic outlook. In this work, sandwich-like Fe, Co, or Ni nanoparticles/reduced graphene oxide (RGO) composites were successfully fabricated via self-assembly and thermal reduction techniques. The characterization results of XRD, Raman spectroscopy, XPS, SEM, TEM, and thermogravimetric analysis showed that the Fe, Co, and Ni nanoparticles were wrapped by flexible RGO nanosheets, showing sandwich structure. Moreover, the loading amounts of Fe, Co, and Ni nanoparticles were further controlled in a wide range. As expected, this unique sandwich structure can not only reduce the agglomeration of magnetic metal nanoparticles and RGO nanosheets, but also improve the impedance matching and the relaxation loss, achieving an attractive microwave absorption performance. For Co/RGO composites, the value of the minimum reflection loss is –50.60 dB, and the effective absorption bandwidth (RL ≤ –10 dB) can cover the entire X-band and Ku-band with a low filling ratio of 25%. Moreover, the synthesis process is simple and does not require complicated equipment and a variety of chemical reagents, which are suitable for large-scale production and possible industrial applications. The present work provides a good design and fabricating avenue for new graphene-based nanocomposites.

Advancement in Graphene-Based Materials and Their Nacre Inspired Composites for Armour Applications-A Review.

The development of armour systems with higher ballistic resistance and light weight has gained considerable attention as an increasing number of countries are recognising the need to build up advanced self-defence system to deter potential military conflicts and threats. Graphene is a two dimensional one-atom thick nanomaterial which possesses excellent tensile strength (130 GPa) and specific penetration energy (10 times higher than steel). It is also lightweight, tough and stiff and is expected to replace the current aramid fibre-based polymer composites. Currently, insights derived from the study of the nacre (natural armour system) are finding applications on the development of artificial nacre structures using graphene-based materials that can achieve high toughness and energy dissipation. The aim of this review is to discuss the potential of graphene-based nanomaterials with regard to the penetration energy, toughness and ballistic limit for personal body armour applications. This review addresses the cutting-edge research in the ballistic performance of graphene-based materials through theoretical, experimentation as well as simulations. The influence of fabrication techniques and interfacial interactions of graphene-based bioinspired polymer composites for ballistic application are also discussed. This review also covers the artificial nacre which is shown to exhibit superior mechanical and toughness behaviours.

Electrochemically Exfoliated Graphene for High-Durability Cement Composites.

The development of radically new types of corrosion-resistant cement composites is nowadays compulsory in view of the continuous increase of concrete consumption combined with the intrinsically defective nature of concrete. Among various additives being employed in the concrete technology, carbon nanomaterials have emerged as extremely powerful components capable of remarkably enhancing nano- and microstructures as well as properties of cement-based composites. In this study, we demonstrate that cement mortar incorporating electrochemically exfoliated graphene (EEG) exhibits significantly improved fluid transport properties. The addition of 0.05 wt % of EEG to ordinary Portland cement mortar results in the reduction of initial and secondary sorptivity values by 21 and 25%, respectively. This leads to the outstanding resistance of EEG-cement composites to highly corrosive environments, namely, chloride and sulfate solutions. These observations, combined with the previously reported remarkable enhancement of the tensile strength of EEG-cement mortars, represent a major step toward the development of highly durable graphene-based cement composites.

Recent developments for antimicrobial applications of graphene-based polymeric composites: A review

Owing to its captivating properties, Graphene-based materials (GMBs) have appeared as a broad-spectrum antimicrobial material and attracting scientists and researchers’ attention. By focusing on the recent advances in the polymeric nanocomposite’s field, current study is positioned on the graphene-based polymeric composites having antibiofilm and antimicrobial activities to confront the current situations of microbial resistance against antibiotics and other drugs. Furthermore, this review summarizes the influence of different factors on the antimicrobial activities of graphene-based polymeric composites like size, shape, number of layers, concentration, dispersibility, and functionalization, and also shed the light on the possible mode of actions of these materials. Graphene-based polymeric composites exert its antimicrobial action by physical damages (e.g., direct sharp edges’ contact to cell membranes of bacteria, wrapping of the bacterial cell, phospholipid extraction, and photo-thermal ablation) and chemical damages (e.g. oxidative-stress and charge transfer). Besides, this review article thoroughly describes the antimicrobial applications of graphene-based polymeric composites, which are because of their good biocompatibility and superior antimicrobial properties such as wound bandages and dressings, antimicrobial coatings, drug delivery, food packaging, hydrogel formation, and water disinfection. Present review may stimulate major concerns, spur further developments, and provide valuable insight into the promising fields.

GO based PVA nanocomposites: tailoring of optical and structural properties of PVA with low percentage of GO nanofillers

Graphene-based polymer composites are gaining interest as a modish class of substance that holds promising angles on diverse applications. In this work, Graphene Oxide (GO) based Polyvinyl Alcohol (PVA) nanocomposites (PVA-GO) have been prepared by employing a facile solution casting method. Low concentrations of GO nanofiller (0.25%, 0.50%, 0.75%, and 1.0%) were used and the result of the use of them over the distinct substantial characteristics of the nanocomposites was evaluated. The different features of the as-synthesized nanocomposites such as optical, structural, chemical, and thermal properties were identified by UV-Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), and Thermo-gravimetric analysis (TGA), respectively. From the structural analysis of the crystallinity of the nanocomposite it is evident that a reduction in crystallinity caused by the amalgamation of the GO nanofiller. FTIR study shows improved interaction between the GO nanofiller and PVA matrix. The incorporation of GO was found to reduce the optical band gap of the nanocomposite both for the direct and indirect transition. The Urbach energy of the nanocomposite increases with the increase of the GO concentration suggests the formation of localized states causing a reduction in the optical band gap. PVA-GO nanocomposites with improved and tunable physical properties synthesized from a simple and economic route may pave a new horizon for polymer-based optoelectronic devices.

Understanding the enhanced electrorheological effect of reduced graphene oxide‐supported polyaniline dielectric nanoplates by a comparative study with graphene oxide as the support core

Graphene has attracted scientific interest as a substrate or additive for developing high-performance stimuli-responsive materials. Research on graphene-based polymer dielectric composites has shown an enhanced electroresponsive electrorheological (ER) effect. However, the mechanism behind the enhanced electroresponse is still incompletely understood. Here, an investigation was performed into dielectric polarization and the ER effect of reduced graphene oxide-supported polyaniline nanoplates by comparing them with pure granular polyaniline and graphene oxide-supported polyaniline nanoplates based on dielectric spectroscopy and rheologic analysis. We discovered that both anisotropic morphology and electrical properties have dominant roles in the enhanced ER effect of reduced graphene oxide-supported polyaniline nanoplates, whereas only anisotropic morphology has a dominant role in the enhanced ER effect of graphene oxide-supported polyaniline nanoplates. The analysis also showed that reduced graphene oxide-supported polyaniline nanoplates have a good ER response to both DC and AC electric field actions in the wide shear rate region. This is highly desirable for practical engineering applications. Therefore, the analysis reveals the reason for the enhanced ER effect of reduced graphene oxide-supported polyaniline nanoplates and also may provide a guide for designing high-performance ER materials for practical engineering applications by combining the advantages of conducting a reduced graphene oxide core and ER active shell.

Preventing Graphene from Restacking via Bioinspired Chemical Inserts: Toward a Superior 2D Micro-supercapacitor Electrode

Graphene-based composites are promising materials for supercapacitors due to the high specific surface area and electrical conductivity of graphene. Reduction of graphene oxide (GO) is a practical approach to obtain a graphene-like material, but it suffers from restacking of the graphene sheets. Herein, a two-dimensional composite electrode based on electrochemically reduced GO (ERGO) and polydopamine (PDA) is reported, where PDA is used as a “bioinspired chemical insert” to tackle with the restacking issue of graphene layers. This green and facile electrochemical fabrication method starts from electroreduction of GO followed by electro-oxidation of dopamine (DA), present in the same electrolyte, by a simple switch between a cathodic and an anodic potential. The optimized ERGO-PDA composite electrode possesses combined features of excellent capacitive behavior, with a relaxation time (τ0) of 0.88 s, high gravimetric and volumetric capacitances (178 F·g–1 and 297 F·cm–3, respectively, at 10 mV·s–1), and finally an excellent cycling stability at 100–2000 mV·s–1 at least for 30,000 cycles. The DA electropolymerization yield monitored by a quartz crystal microbalance and X-ray diffraction measurements demonstrate that PDA is formed between the graphene sheets which prevents the sheets from restacking and facilitates species diffusion inside the composite, leading to a volumetric energy density of 8.6 mWh·cm–3 for a power density of 7.8 W·cm–3. Additionally, the electrochemical quartz crystal microbalance demonstrates a dominant cationic charge compensation and a very efficient interfacial transfer characteristic since a totally reversible mass response during charge/discharge was observed for the optimized ERGO-PDA electrode.

Highly Thermally Conductive 3D Printed Graphene Filled Polymer Composites for Scalable Thermal Management Applications.

Efficient thermal transportation in a preferred direction is highly favorable for thermal management issues. The combination of 3D printing and two-dimensional (2D) materials such as graphene, BN, and so on enables infinite possibilities for hierarchically aligned structure programming. In this work, we report the formation of the asymmetrically aligned structure of graphene filled thermoplastic polyurethane (TPU) composites during 3D printing process. The as-printed vertically aligned structure demonstrates a through-plane thermal conductivity (TC) up to 12 W m-1 K-1 at 45 wt % graphene content, which is ∼8 times of that of a horizontally printed structure and surpasses many of the traditional particle reinforced polymer composites. The superior TC is mainly attributed to the anisotropic structure design that benefited from the preferable degree of orientation of graphene and the multiscale dense structure realized by finely controlling the printing parameters. Finite element method (FEM) confirms the essential impact of anisotropic TC design for highly thermal conductive composites. This study provides an effective way to develop 3D printed graphene-based polymer composites for scalable thermal-related applications such as battery thermal management, electric packaging, and so on.

Rational construction of porous N-doped Fe2O3 films on porous graphene foams by molecular layer deposition for tunable microwave absorption

Graphene-based materials with porous microstructure have attracted immense attentions due to their wide application in microwave absorption. However, constructing magnetic film with both porous microstructure and uniform pore size by using traditional methods still remains a challenge. To overcome this problem, we reported a facile strategy of molecular layer deposition (MLD) for successfully fabrication of the hybrid-architecture of porous graphene foams and nitrogen-doped porous Fe2O3 films. The surfaces of porous graphene foams are uniformly covered by porous Fe2O3 films without aggregation and the pore structures are widely distributed. The porous graphene-based composites exhibit remarkably enhanced microwave absorption performance compared to the pristine graphene foams. The minimum reflection loss value is increased by approximately 8 times, reaching −64.36 dB with a thickness of only 2.18 mm. More importantly, the absorption property can be precisely modulated by tuning the MLD cycle numbers and effective absorption bandwidth covers 3.04–18.0 GHz by adjusting the thickness from 1.0 to 5.0 mm. This work provides new insights for exploring novel and high-performance graphene-based microwave absorbents and offers a new idea to rationally design three-dimensional composites with porous magnetic films.

Photo-electrochemical water splitting through graphene-based ZnS composites for H2 production

Hydrogen production through photo-electrochemical (PEC) water splitting is obstructed by strong forces of attraction between H2O molecules and charge recombination in semiconductor materials. To overcome such limitations, graphene-based ZnS heterojunction photo-anode is developed that magnifies the PEC performance by improving optical properties and enhancing charge separation. ZnS composites with different weight ratios (2%, 4%, and 6%) of graphene are prepared through the hydrothermal process and characterized by using x-rays diffraction (XRD), transmission electron microscopy (TEM), uv–vis spectroscopy, and x-rays photon spectroscopy (XPS) to obtain crystallinity, morphology, uv–vis spectra and binding energy of prepared materials, respectively. Synergic effect of ZnS composite with 6% weight loading of graphene achieved a notable photo-current density (2.23 mA cm−2 at 0.72 V vs. RHE) under illumination. Moreover, 3.7 folds increased hydrogen yield of 0.049 μmoles cm−2 min−1 by 10 mg mass loading of material on fluorine-doped tin oxide (FTO) glass slide is obtained as compared to pure ZnS with hydrogen yield of 0.049 μmoles cm−2 min−1.

Graphene-based Composites for the Thermal Decomposition of Energetic Materials

Owing to its remarkable mechanical, electrical and thermal properties, graphene has been a hot area of composites research in the past decade, including the field of energetic materials. Graphene has been widely applied in enhancing the physical properties of energetic materials, such as solid composite propellants. Through the way of adding different forms of graphene into the matrix of solid propellants, their thermal decomposition performance can be effectively improved. In this paper, we reviewed the status and challenges of the application of graphene in the thermal decomposition of composite solid propellant. Moreover, the main preparation methods and material structures of graphene are reviewed. We can conclude that graphene and its derivatives can enhance the catalytic effect remarkably, which can be attributed to the large specific surface area of graphene that makes the uniformly dispersed catalyst particles and the more catalyst active sites. Meanwhile, graphene possesses the high thermal conductivity, making the rapider heat diffusion, which can promote the decomposition reactions of the energetic components in solid propellants. Graphene and catalyst work synergistically in their thermal decomposition. More than this, the main methods to improve the thermal decomposition of energetic components of composite propellants and their effects on decomposition temperature reduction are systematically summarized, respectively.

Synthesis of ultralight three-dimensional nitrogen-doped reduced graphene oxide/multi-walled carbon nanotubes/zinc ferrite composite aerogel for highly efficient electromagnetic wave absorption

Developing light-weight, thin thickness and high-efficiency electromagnetic wave (EMW) absorbers was regarded as an effective strategy for dealing with the increasingly serious problem of electromagnetic radiation pollution. Herein, nitrogen-doped reduced graphene oxide/multi-walled carbon nanotubes/zinc ferrite (NRGO/MWCNTs/ZnFe2O4) composite aerogel was synthesized via solvothermal followed by hydrothermal and lyophilization processes. Morphological characterization results manifested that the attained ternary composite aerogel displayed unique three-dimensional porous netlike structure, which was composed of partial stack of adjacent NRGO sheets entangled by MWCNTs and decorated with ZnFe2O4 microspheres. Moreover, the influences of complexing with conductive MWCNTs and magnetic ZnFe2O4, and filler contents on the EMW attenuation performance of ternary composite aerogel were examined. Significantly, the ternary composite aerogel exhibited notably strengthened EMW absorption capacity in comparison with NRGO/MWCNTs composite aerogel, NRGO aerogel and ZnFe2O4 microspheres. The minimum reflection loss (RLmin) was up to −52.6 dB at a thin matching thickness of 1.7 mm and effective absorption bandwidth (EAB) was 5.1 GHz (12.7–17.8 GHz) under an ultrathin thickness of 1.65 mm with a low filler content of 10 wt%. Remarkably, the |SRLmin| (|specific RLmin value per thickness|) could achieve 30.9 dB/mm, which overwhelmed almost all the reported RGO-based composite aerogels. Besides, the possible EMW absorption mechanisms of as-synthesized ternary composite aerogel were proposed. It was believed that our results provided a valuable guidance for fabricating graphene-based composites with three-dimensional netlike structure as light-weight, thin thickness and high-performance EMW absorbers.

Innovative construction materials: graphene-based smart composites

Innovative construction materials: graphene-based smart composites

Effective Strategies, Mechanisms, and Photocatalytic Efficiency of Semiconductor Nanomaterials Incorporating rGO for Environmental Contaminant Degradation

The water pollution problems severely affect the natural water resources due to the large disposal of dyes, heavy metals, antibiotics, and pesticides. Advanced oxidation processes (AOP) have been developed using semiconductor nanomaterials as photocatalysts for water treatment as an essential strategy to minimize environmental pollution. Significant research efforts have been dedicated over the past few years to enhancing the photocatalytic efficiencies of semiconductor nanomaterials. Graphene-based composites created by integrating reduced graphene oxide (rGO) into various semiconductor nanomaterials enable the unique characteristics of graphene, such as the extended range of light absorption, the separation of charges, and the high capacity of adsorption of pollutants. Therefore, rGO-based composites improve the overall visible-light photocatalytic efficiency and lead to a new pathway for high-performance photocatalysts’ potential applications. This brief review illustrates the strategies of combining rGO with various semiconductor nanomaterials and focuses primarily on modification and efficiency towards environmental contaminants.

A review of performance improvement strategies for graphene oxide-based and graphene-based membranes in water treatment

In the past few decades, due to the rapid development of industry and the rapid growth of population, emissions of pollutants to the environment have increased dramatically, and the demand for drinking water is also increasing. Water treatment is a matter of concern because it is directly related to the health of humans and wildlife. Graphene and its derivatives have potential applications in seawater desalination and wastewater treatment due to their unique pore structure and ionic molecular sieving separation capabilities. Graphene, graphene oxide (GO), and reduced graphene oxide (rGO) can be formulated into nanoporous materials and composites with tunable properties that can be optimized for water filtration. Methods for perforating graphene include ion etching/ion bombardment and electron beam nanometer engraving, which are briefly introduced in this paper. Graphene-based composites further expand the capabilities of graphene in seawater desalination and wastewater treatment, by introducing new features and properties. In this review, the performance improvement of graphene-based separation membranes in decontamination and desalination in recent years is reviewed in detail. This review focuses on improving the performance of graphene-based membranes for separation, decontamination, and seawater desalination applications, by discussing how various modifications and preparation methods impact important performance properties, including water permeance, selectivity, rejection of solutes, membrane mechanical strength, and antifouling characteristics. We also discuss the outlook for future development of graphene-based membranes.

Highly Efficient Preparation of Graphite Oxide without Water Enhanced Oxidation

Graphite oxide has become an important precursor for graphene oxide, reduced graphene oxide, and a wide range of other graphene-based materials or composites. In numerous Hummers’ methods for the p...

The Possible Detriment of Oxygen in Creep of Alumina and Zirconia Ceramic Composites Reinforced with Graphene.

This paper aims to give an answer to the following question: is the oxidation of graphene a critical issue for high-temperature plasticity in graphene-reinforced ceramics? To give a convincing reply, we will focus on two very different graphene-based ceramic composites: reduced graphene oxide (rGO)-reinforced alumina (α-Al2O3) and reduced graphene oxide (rGO)-reinforced yttria tetragonal zirconia (t-ZrO2). The processing of the powders has been made using a colloidal route, and after that, a spark plasma sintering process was performed in order to densify the samples. Creep tests were performed at temperatures between 1200–1250 °C in an argon atmosphere. The microstructure obtained by SEM of the sintered and tested specimens was characterized quantitatively to elucidate the deformation mechanism. Raman spectroscopy was carried out to check the integrity of the graphene. The average grain size was in the order of 1 µm and the shape factor was 0.7 for all the studied materials. The integrity of the graphene was checked before and after the creep experiments. The careful analysis of the creep tests shows that graphene oxide or its reduced version are not efficient phases for creep resistance improvement in general, contrary to what is reported elsewhere. However, the results permit the suggestion of a creep improvement in nanocomposites at a very high temperature regime due to an enhanced reactivity of oxygen between carbon and alumina interfaces. In the case of zirconia, the results give us the conclusion that the oxidation of graphene is a highly detrimental issue regarding the improvement of high-temperature plasticity.

Structural and functional applications of 3D-printed graphene-based architectures

Based on the huge potential of graphene-based composites in electrical, thermal and mechanical applications, which have been widely used in electronics, energy storage and conversion, sensors and structural composites, the assembly and three-dimensional (3D) configuration of graphene nanosheets is an important routine to realize and even optimize its excellent properties. Considering the anisotropy of two-dimensional (2D) graphene and the accuracy of 3D architecture, 3D printing technology stands out in the preparation of periodic and diversified 3D graphene due to its efficient and controllable construction process. Moreover, the interconnected graphene conductive network and lightweight structural regulation can realize the integration of structure and function from low-dimensional to multidimensional. In these circumstances, the structural design and related functional applications of the printed graphene-based architecture are reviewed, and it is important to understand the inks properties, macro-microstructural regulation and corresponding application prospects. Besides, a summary and outlook is prepared in the last part, which points out the application difficulties and future development of 3D-printed graphene-based architecture.

Graphene-Based Composites for Phosphate Removal.

A variety of methods, including chemical precipitation, biological phosphorus elimination, and adsorption, have been described to effectively eliminate phosphorus (P) in the form of phosphate (PO43–) from wastewater sources. Adsorption is a simple and easy method. It shows excellent removal performance, cost effectiveness, and the substantial option of adsorbent materials. Therefore, it has been recognized as a practical, environmentally friendly, and reliable treatment method for eliminating P. Nanocomposites have been deployed to remove P from wastewater via adsorption. Nanocomposites offer low-temperature alteration, high specific surface area, adjustable surface chemistry, pore size, many adsorption sites, and rapid intraparticle diffusion distances. In this Mini-Review, we have aimed to summarize the last eight years of progress in P removal using graphene-based composites via adsorption. Ultimately, future perspectives have been presented to boost the progress of this encouraging field.