Applications Of Graphene Research Articles

A review on energy conversion applications of graphene-based nanomaterials and environmental remediation

Graphene is popular for its striking physicochemical properties. Conversely, the application of pure graphene is greatly limited inert owing to its inert nature. Therefore, one of the greatest approaches to investigate graphene's intrinsic features is by functionalization. The highly conductive rGO (reduced graphene oxide) sheet is generally used as a suitable solid support for catalysts that not only inhibit carrier recombination but also improve carrier mobility to power a variety of solar energy conversion applications. According to various studies, the photocatalytic H2 production rate was found to be significantly increased by the potential electron storing and transferring characteristics of the rGO sheet, going from 16656 mol/h for Cu2O-TiO2 to 110968 mol/h for Cu2O-TiO2/rGO, or an increase of at least 7 times. The Cu2O-rGO-C3N4 photocatalyst 139 considerably enhanced the photocatalytic 4-nitrophenol reduction in comparison to the Cu2O-C3N4 photocatalyst alone. The oxygen reduction reaction, photocatalytic water splitting, photocatalytic degradation of organic contaminants, and polymer solar cells were only a few of the applications that rGO-based nanocomposites were used for in the current study.

Review on 3D-printed graphene-reinforced composites for structural applications

The reasonable macro-micro structural design presents a significant impact on the mechanical properties of structural composites, and the progress of three-dimensional (3D) printing provides an opportunity for efficient and controllable construction of multi-dimensional lightweight and high-strength composites. Recently, carbon-based nanomaterials are in the spotlight as nanofillers of structural composites for the huge available specific surface area and excellent mechanical properties, especially graphene, the unique two-dimensional (2D) nanosheet with superior Young’s modulus, intrinsic strength, and significantly outstanding stretchability. For the application of graphene in 3D printing, the macro-assembly can fabricate complex 3D objects with any size and configuration, while realizing the highly oriented distribution and the construction of a penetrating structural network by micro-regulation. Herein, the multiscale structural composites reinforced by 3D-printed graphene are outlined, including ceramic matrix composites, polymer matrix composites, and metal matrix composites. Moreover, the current challenges and future application prospects in this fast-growing field are predicted.

A critical review on the properties and energy storage applications of graphene oxide/layered double hydroxides and graphene oxide/MXenes

A critical review on the properties and energy storage applications of graphene oxide/layered double hydroxides and graphene oxide/MXenes

Effects of Crack Formation on the Mechanical Properties of Bilayer Graphene: A Comparative Analysis

We present a molecular dynamics simulation study on the effects of crack formation on the mechanical properties of bilayer graphene. Bilayer graphene possesses unique electronic properties that can be modified by applying a voltage, making it an attractive material for various applications. We examined how the mechanical properties of bilayer graphene vary under various crack configurations and temperatures, measuring Young’s modulus, fracture toughness, fracture strain, and fracture stress. We compared the effect of crack presence on single and both layers and found the appearance of double peaks in the stress–strain curves in the case of a monolayer crack, indicating a subsequent fracture of the cracked layer and the uncracked layer. We also examined the effect of crack shape, size, and orientation on mechanical properties, including circular, hexagonal, and rectangular cracks along two axes. We found that both circular and hexagonal cracks had a smaller Young’s modulus and toughness than rectangular cracks, and the orientation of the crack had a significant impact on the mechanical properties, with a 2.5-times higher toughness for cracks with a length of 15Å. Additionally, we found that Young’s modulus decreases with increasing temperature in bilayer graphene with cracks on both layers. Our findings provide valuable insights into the potential applications of bilayer graphene in the design of advanced nanoscale electronic devices.

A comprehensive review of heat transfer enhancement of heat exchanger, heat pipe and electronic components using graphene

The industrial growth of any country depends on energy source availability and utilization of energy for various applications. The heat exchanger is a heat transfer device which is most widely used in various applications for effective heat transfer between cold and hot fluids. Any improvement in heat transfer results in enhancement in overall performance of the device. Hence various techniques are used to improve the heat transfer. The solid particles which have higher thermal conductivity and can be used to improve the heat transfer between hot and cold fluids. The thermal conductivity of graphene-based nanoparticle is high, and it has low erosion, corrosion, higher stability, etc. Hence graphene-based nanoparticle is chosen in various heat transfer applications. The use of graphene-based nanoparticles increases the heat transfer and hence it can reduce the size of the heat transfer equipment. This paper critically reviews various applications of graphene in different types of heat exchangers, electronic devices challenges and opportunities, by highlighting the advantages of using graphene.

Proton absorption and penetration behaviors in Pt‐supported graphene

AbstractThe proton (H+) conductivity is very crucial for graphene applications in the field of proton membrane fuel cell (PEMFC), and the absorption and penetration of H+ are fundamental steps for the H+ conduction. In order to improve the H+ conductivity in graphene, loading catalytically active metals such as Pt on the graphene surface is an effective method. First‐principles calculations were thus employed to investigate the absorption and penetration behaviors of H+ on Pt‐supported graphene, and the doping effect of substitutional elements such as B, N, and S were also involved. It is found that the absorption and penetration behaviors of H+ on Pt‐supported graphene depend strongly on the loaded Pt atoms and doped elements. From the viewpoint of absorption energy, N is favorable for the H+ absorption in Pt‐supported graphene, while B and S are unfavorable. From the perspective of penetration barrier, B‐doping is beneficial for the penetration of H+ in Pt‐supported graphene, while N‐ and S‐doping are unbeneficial. On the other hand, Pt loading has a positive effect on the H+ absorption on pristine, B‐ and N‐doped graphene, while has a negative effect on S‐doped graphene. Meanwhile, Pt loading has a positive effect on the penetration of H+ in pristine, B‐, N‐ and S‐doped graphene. The absorption and penetration behaviors of H+ in Pt‐supported graphene are closely dependent on electronic properties, and will be influenced by the introduction of impurity elements.

Effects of Graphene on Soil Water-Retention Curve, van Genuchten Parameters, and Soil Pore Size Distribution—A Comparison with Traditional Soil Conditioners

Graphene waste has had enormous growth due to many industrial applications. Agriculture exploits waste through the circular economy, and graphene waste is thereby investigated in this study as a soil conditioner for improving the physical–hydraulic properties of soil. Experiments were performed on three differently textured soils amended with traditional soil conditioners (compost, biochar, and zeolites) and graphene. The conditioners were applied at two different doses of 10% and 5% dry weight (d.w.) for compost, biochar, and zeolites, and 1.0% and 0.5% d.w. for graphene. We compared (i) the major porosity classes related to water-retention characteristics (drainage, storage, and residual porosity), (ii) bulk density, and (iii) van Genuchten water-retention curve (WRC) characteristics. Graphene application caused the largest decrease in dry bulk density (ρb), lowering the soil bulk density by about 25%. In fact, graphene had ρb of 0.01 g/cm3. The effects of graphene were more intense in the finer soil. Compost and biochar showed similar effects, but of lower magnitude compared to those of graphene, with ρb of 0.7 and 0.28 g/cm3, respectively. Although zeolites had ρb of 0.62 g/cm3, they showed quite different behavior in increasing the mixtures’ ρb. Graphene and biochar showed the most pronounced effects in the clayey soil, where storage porosity showed a reduction of >30% compared to the control. For storage porosity, the graphene treatments did not show statistically significant differences compared to the control. The results show that, when the conditioner increased drainage porosity, there was a high probability of a concomitant reduction in storage porosity. This finding indicates that graphene use for improving soil aeration and drainage conditions is viable, especially in fine soils.

The First-Water-Layer Evolution at the Graphene/Water Interface under Different Electro-Modulated Hydrophilic Conditions Observed by Suspended/Supported Field-Effect-Device Architectures.

Interfacial water molecules affect carrier transportation within graphene and related applications. Without proper tools, however, most of the previous works focus on simulation modeling rather than experimental validation. To overcome this obstacle, a series of graphene field-effect transistors (GFETs) with suspended (substrate-free, SF) and supported (oxide-supported, OS) configurations are developed to investigate the graphene-water interface under different hydrophilic conditions. With deionized water environments, in our experiments, the electrical transportation behaviors of the graphene mainly originate from the evolution of the interfacial water-molecule arrangement. Also, these current-voltage behaviors can be used to elucidate the first-water layer at the graphene-water interface. For SF-GFET, our experimental results show positive hysteresis in electrical transportation. These imply highly ordered interfacial water molecules with a separated-ionic distributed structure. For OS-GFET, on the contrary, the negative hysteresis shows the formation of the hydrogen-bond interaction between the interfacial water layer and the SiO2 substrate under the graphene. This interaction further promotes current conduction through the graphene/water interface. In addition, the net current-voltage relationship also indicates the energy required to change the orientation of the first-layer water molecules during electro-potential change. Therefore, our work gives an insight into graphene-water interfacial evolution with field-effect modulation. Furthermore, this experimental architecture also paves the way for investigating 2D solid-liquid interfacial features.

Graphene and boron nitride foams for smart functional applications

AbstractGraphene and boron nitride (BN) foams, as two types of three‐dimensional (3D) nanomaterials consisting of two‐dimensional (2D) nanosheets, can inherit a series of excellent properties of the 2D individuals. The internal 3D network can prevent aggregation or restacking between isolated graphene or BN nanosheets, and provide a highway for phonon/electron transports. Moreover, the interconnected porous structure creates a continual channel for the mass exchange of exotic species. The light‐element graphene and BN foams can thus possess the characteristics of low density, high porosity, high surface area, and excellent mechanical, thermal, and electrical properties. Benefiting from these advantages, they show a wide range of applications. The usual synthesis methods and the recent functional applications of graphene and BN foams are reviewed herein, including their applications as supporting materials, elastic materials, acoustic shielding materials, thermal interface materials, electromagnetic shielding materials, adsorption materials, electrocatalysis and thermal catalyses materials, electrochemical energy storage, and thermal energy storage materials. Current challenges and outlooks are additionally discussed.

Graphene Utilization for Efficient Energy Storage and Potential Applications: Challenges and Future Implementations

Allotropes of carbon are responsible for discovering the three significant carbon-based compounds, fullerene, carbon nanotubes, and graphene. Over the last few decades, groundbreaking graphene with the finest two-dimensional atomic structure has emerged as the driving force behind new research and development because of its remarkable mechanical, electrical, thermal, and optical functionalities with high surface area. Synthesis of graphene oxide (GO) and reduced graphene oxide (rGO) has resulted in numerous applications that previously had not been possible, incorporating sensing and adsorbent properties. Our study covers the most prevalent synthetic methods for making these graphene derivatives and how these methods impact the material’s main features. In particular, it emphasizes the application to water purification, CO2 capture, biomedical, potential energy storage, and conversion applications. Finally, we look at the future of sustainable utilization, its applications, and the challenges which must be solved for efficient application of graphene at large scales. Graphene-based derivative implementations, obstacles, and prospects for further research and development are also examined in this review paper.

Strong Bending Distortion of a Supercoronene Graphene Model upon Adsorption of Lanthanide Atoms

Numerous applications of graphene involve quasi-infinite sheets, as well as finite structures with edges, pores, graphene quantum dots, etc. In theoretical studies of adsorption of diverse chemical species, including single atoms, molecules, cations, and anions, graphene usually behaves as a very rigid planar structure. However, we found that when adsorbing lanthanide atoms, finite size structures, represented by the widely used supercoronene model, can undergo considerable distortion, and the degree of distortion depends on the number of unpaired electrons, reaching a maximum for Gd (eight unpaired electrons). Lanthanides closely approach the supercoronene surface and increase the interaction energy. Extrapolating to real-world systems, one can expect the existence and magnitude of lanthanide-induced distortion to depend on the size of graphene structures. Quasi-infinite or very large graphene sheets are too rigid to undergo such bending, but it becomes tangible for graphene quantum dots and for atom adsorption closer to graphene edges.

Aramid-based highly conductive composite films by incorporating graphene for electromagnetic interference shielding and Joule heating applications

With the development of modern electronic devices, high-performance polymer-based conductive composites are urgently needed. However, the poor thermal stability of most polymers, the high content of conducive fillers, and the unsatisfied performance efficiency of most composites limited their application in high high-end areas. Both aramid and graphene are fantastic engineering materials, their composites are expected to have desirable performances. Herein, we demonstrate the preparation of polymerization-induced aramid nanofiber (PANF)/reduced graphene oxide (rGO) composite films through a simple yet efficient strategy. The assembly of the two components were achieved by a low cost and scalable vacuum-assisted filtration method. With PANFs serving as the matrix and rGO serving as the filler, PANF/rGO composite films with multilayer structure, excellent mechanical property, superior thermal stability and flame retardancy were obtained. The electrical conductivity of composite films can reach 4.8 × 103 S/m with a rGO content of 20%. Correspondingly, the composite films show excellent electromagnetic interference shielding performance and the shielding effectiveness of PANF/rGO composite film with a thickness of 30 μm can reach 33.6 dB. Furthermore, the composite films also exhibit excellent Joule heating performance with a wide heating temperature range (30–180 °C). These advantages can promote the practical engineering applications of aramid and graphene.

Formation of Large-Area Twisted Bilayer Graphene on Ni(111) Film via Ambient Pressure Chemical Vapor Deposition

Due to the destruction of the intrinsic symmetry between the layers, twisted bilayer graphene has the advantages of available interlayer coupling, tunable electronic bandgap, and diverse phonon dispersion features, which offers a unique platform for the advanced electronic devices. The segregation growth of large-area twisted bilayer graphene on Ni(111) film by ambient pressure chemical vapor deposition (APCVD) methods is presented in this paper. The growth kinetics include two main aspects of the catalytic reaction of methane on the Ni surface and the carbon segregation from the Ni bulk. The large-area twisted bilayer graphene (TBG) can be fabricated by controlling carbon segregation for the continuous second layer graphene that is rotated relative to the first layer graphene. Low energy electron diffraction (LEED) studies reveal a dominant twist angle of about 22.7°. The analysis shows that the dominant twist angle is closely related to the stable energy structure of TBG with the smallest moiré periodicity. Besides, the other twist angles of TBG are also formed in vicinity of the dominant angle, confirmed by microscopic observations with selected area electron diffraction (SAED). The work in this paper provides a convenient route for the synthesis of TBG on Ni(111) substrate, which can promote the application of twisted graphene in future photoelectric and spintronic devices.

Contemporary updates on bioremediation applications of graphene and its composites

Graphene, a 2D single-layered carbon sp2 hybrid substance set in a honeycomb network, is widespread in many carbon-based materials. Due to its extraordinary optical, electrical, thermal, mechanical, and magnetic competences as well as its significant specific surface area, it has attracted a lot of interest recently. Synthesizing graphene refers to any process for creating or extracting the material, depending on the desired purity, size, and efflorescence of the finished good. Numerous methods have been employed for graphene synthesis categorized as top-down procedures and bottom-up procedures. Graphene finds its implementations in various industries such as electronics, energy, chemical, transport, defence, and biomedical areas such as accurate biosensing. It has been widely used in water treatment as a binder for organic contaminants and heavy metals. Many researches have fixated on creating various modified graphene, graphene oxide composites, graphene nanoparticle composites and semiconductor hybrids of graphene for contaminant removal from water. In this review, we have tried to address various production methods for graphene and its composites along with their advantages and disadvantages. Furthermore, we have presented a summary on graphene's outstanding immobilization of a variety of contaminants like toxic heavy metals, organic dyes, inorganic pollutants and pharmaceutical wastes. Additionally, a development of graphene-based microbial fuel cell (MFC) has been evaluated in an effort to produce ecological wastewater treatment and bioelectricity.

Environmental Application of Graphene and Its Forms for Wastewater Treatment: a Sustainable Solution Toward Improved Public Health.

Public health is seriously jeopardized in developing countries due to poor sanitation and the presence of persistent pollutants in natural water bodies. Open dumping, wastewater discharge without proper treatment and atmospheric fallout of the organic and inorganic pollutants are the main causes behind the poor condition. Some of the pollutants pose a greater risk due to their toxicity and persistence. Such a class of pollutants are known as chemical contaminants of emerging concern (CECC), including antibiotics and drug residues, endocrine disruptors, pesticides and micro- and nano-plastics. Conventional treatment methods cannot treat them properly and are often associated with several disadvantages. However, the chronological development of techniques and materials for their treatment has exhibited graphene as an efficient candidate for environmental remediation. This current review considers the various graphene-based materials, their properties, advancement in synthesis methods with time and their detailed application in removing dyes, antibiotics and heavy metals. It has been discussed how graphene and its derivatives exhibit unique electronic, mechanical, structural and thermal properties. In this paper, the mechanism of adsorption and degradation using these graphene-based materials has also been discussed vividly. In addition to this, a bibliographic analysis was performed to identify the trend of research related to graphene and its derivatives in the adsorption and degradation of pollutants round the globe reflected by the publications. Therefore, this review can be instrumental in understanding the fact that further development of graphene-based materials and their mass production can provide a very effective and economical wastewater treatment method.

Application of high surface area graphene for enhanced heat transfer co-efficient – An experimental study

Increased heat transmission has contributed significantly to cost and energy savings. The desire for compact gadgets with the finest performance, correct working, and long lifespan is being fuelled by today's scientific and technological advancements. The researchers were able to introduce a fresh kind of fluid with a mixture that was referred to as “Nanofluids” due to their superior thermal transfer capabilities compared to regular fluids. Applications for nanofluids in the electrical and other cooling industries are numerous. In this work, hydrogen exfoliated Graphene of two types i.e. multilayer Graphene designated as L- type and monolayer Graphene designated as A+-type is diffused in pure deionized (DI) water and also in deionized water blended with ammonium hydroxide (NH4OH) to prepare the Graphene-based nanofluid samples. In a concentric-pipe heat exchanger, the prepared nanofluids are utilised to calculate the heat transfer co-efficients. Samples are experimentally investigated to study the outcome of weight concentration and pH on The Heat Transfer Co-efficient (HTC). Results have shown that the HTC is higher for all nanofluid samples than that of water at all the flow rates studied. Six nanofluid samples are prepared with two volume fractions of 0.005% and 0.01%. Three samples were prepared with each of L-type Graphene and A+-type Graphene materials. For sample1 which is prepared by dispersing 0.5 gm of L-type Graphene in 10 L of water, the improvement in combined heat transfer co-efficient observed was 14.5 % over water. For sample 2 prepared by adding a further 50 ml of NH4OH to the sample 1 enhancement over water is observed to be 20.2%. 1 g of L-type graphene is dissolved in ten litres of water to create Sample 3, which has a 24.5% improvement in combined HTC. For the nanofluid samples 4, 5 and 6 prepared with A+-Type Graphene, the corresponding increase in combined heat transfer co-efficient s observed were 44.6 %, 50.2%, and 53.6% respectively. In comparison to L-type samples, nanofluid samples made with A + -type Graphene were shown to provide better thermal performance.

Potential Biomedical Limitations of Graphene Nanomaterials.

Graphene-family nanomaterials (GFNs) possess mechanical stiffness, optical properties, and biocompatibility making them promising materials for biomedical applications. However, to realize the potential of graphene in biomedicine, it must overcome several challenges that arise when it enters the body's circulatory system. Current research focuses on the development of tumor-targeting devices using graphene, but GFNs accumulated in different tissues and cells through different pathways, which can cause toxic reactions leading to cell apoptosis and body dysfunction when the accumulated amount exceeds a certain limit. In addition, as a foreign substance, graphene can induce complex inflammatory reactions with immune cells and inflammatory factors, potentially enhancing or impairing the body's immune function. This review discusses the biomedical applications of graphene, the effects of graphene materials on human immune function, and the biotoxicity of graphene materials.

Wettability of Graphene Coated on Aluminum Substrate with Microstructure Modification

Background: As a new type of coating material, graphene has an important application prospect in creating hydrophobicity on the material surface. It can be seen that research on the wettability of graphene has a very actual significance in its application. Graphene membrane can change the wettability of the aluminum surface effectively. It can be combined with the traditional method to tune the wettability of the metal surface. Adding the microstructure is a very common method for changing the wettability. Therefore, the results have guided significance for the practical application of graphene in controlling the wettability of aluminum substrate with microstructure. Methods: This paper uses molecular dynamics to simulate graphene’s adsorption and wetting behavior on the aluminum substrate with microstructure and to calculate energy changes in the two processes. Results: The adsorption state of graphene is related to the aspect ratio of the microstructure. When the aspect ratios of the microstructure become larger, the graphene can be completely absorbed by the substrate, causing larger binding free energy and higher adhesion spontaneity of graphene. The wetting contact angles of the substrate with graphene are significantly higher than those of the aluminum substrate without graphene. Conclusion: The aspect ratio can influence the free energy and the binding energy, causing different states in graphene. The large aspect ratio will increase the absolute value of the free energy and release more binding energy, causing a more stable state. The graphene may prevent the deformation of the hydrogen bond and cause worse wettability. The results have been of great significance for the practical application of graphene in controlling the wettability of aluminum substrate with microstructure.

Regulation of the Electronic Properties of Graphene via Organic Molecular Intercalation

Stable, efficient, and flexible regulation of the carrier types and concentrations of graphene is important to its multifunctional application. Here, we have synthesized n- and p-type graphene superlattices which are named as Gr/TBA and Gr/Ac via the electrochemical intercalation of organic tetrabutyl ammonium and acetate, respectively. The crystal structure characterization demonstrated that the interlayer spacing of the high-quality Gr/TBA and Gr/Ac was larger than that of pristine graphene. Hall effect measurements indicated that Gr/TBA and Gr/Ac showed n-type and p-type conductive behaviors, respectively. The carrier concentrations and mobility can be effectively tuned by the intercalated organic molecules. The regulation of the electronic properties of graphene via intercalation should result from the electron transfer between graphene and the corresponding organic molecules. Moreover, we further show that the resulting Gr/TBA and Gr/Ac feature excellent stability (chemicals and air), with no apparent change in carrier concentration. Our work provides a new way to regulate the electronic properties of graphene and broaden the application of graphene in multifunctional electrical devices.

C60 filling-enabled tribological improvement of graphene in conformal contact with a rough substrate

Graphene has great potential in the field of solid lubricity due to its superlow friction and high wear resistance. However, the excellent tribological performance of graphene is degraded when it conformally contacts with a rough substrate. This work proposes a novel method to improve the tribological performance of graphene on a rough Si/SiO2 substrate by filling grooves on the substrate surface with C60 molecules. When C60 filling is not performed, the friction force on the graphene surface increases rapidly at the groove edges where graphene presents large out-of-plane deformation due to its conformal contact with the substrate. Inspiringly, such high friction force is reduced by one order of magnitude when C60 filling is introduced to provide out-of-plane support to graphene for preventing its conformal contact with the substrate. Meanwhile, the high mechanical strength of C60 molecules enables a greater than 5-fold strengthening of the load-carrying capacity of graphene, which greatly improves its wear resistance on the rough substrate. These observations are helpful in promoting the tribological application of graphene by diminishing its conformal contact with the rough substrate.