Method For Synthesis Of Graphene Research Articles

Laser‐Induced Porous Graphene/CuO Composite for Efficient Interfacial Solar Steam Generation

AbstractInterfacial solar steam generation can produce clean water in an environmentally friendly and efficient way. The evaporator employing graphene as a photothermal conversion material represents an excellent paradigm within the realm of interfacial evaporators. However, existing graphene materials exhibit a certain degree of hydrophobicity and are associated with intricate manufacturing processes. Hence, the study proposes a hydrophilic composite graphene‐based material incorporating CuO, which is fabricated through a straightforward laser‐induced graphene synthesis method directly onto a polyimide film coated with CuCl2. Due to the fast capillary performance endowed by the enhanced hydrophilicity and hierarchical structural morphology, the assembled laser‐induced‐graphene evaporator achieves an evaporation rate of 2.54 kg m−2 h−1 under 1 sun irradiation with an evaporation efficiency of 91.1%, while also demonstrating excellent desalination capabilities. The as‐prepared graphene‐based evaporator has significant potential for desalination and wastewater treatment applications, offering an effective solution to address clean water challenges in remote areas.

Investigation of picosecond laser-induced graphene for dopamine sensing: Influence of laser wavelength on structural and electrochemical performance

This research focuses on a straightforward synthesis method for laser-induced graphene using green (532 nm) and UV (355 nm) picosecond laser irradiation of graphene oxide dispersion. Structural analysis revealed that the laser operating at 355 nm is more favorable to producing a product with a higher content of the restored sp2 network, a higher graphene in-plane crystallite size, a higher concentration of pyrrolic N, and higher values of the optical bandgap. Conversely, the 532 nm laser yielded a sample with higher concentrations of epoxy groups, sp3 defects, and amorphous carbon. Electrochemical analysis for dopamine determination showed potential for both samples as electrode materials. However, the analytical parameters of the sample treated with the 355 nm laser surpass those of the 532 nm laser. It was assumed that the enhanced electrochemical activity results from the presence of pyrrolic N and vacancies in the structure of the sample treated with the 355 nm laser.

Unconventional eco-friendly synthesis of graphene and its electrochemical analysis

In response to the growing demand for sustainable graphene synthesis methods, traditionally characterized by harsh conditions and prolonged processing, we present an innovative approach. Here, graphene is synthesized utilizing melaleuca alternifolia, a natural resource, under mild conditions of cold plasma. This method not only aligns with the increasing need for environmentally friendly processes but also boasts efficiency, producing graphene within seconds. Our investigation employs various analytical techniques, including Raman spectroscopy, confirming the successful synthesis of graphene. The distinctive peaks identified in the spectroscopic analysis validate the high quality of the graphene material produced. Beyond synthesis, our study delves into the electrochemical properties of the synthesized graphene. Rigorous testing with real biomolecules reveals enhanced current peaks, underscoring the potential applications of graphene in the realm of electrochemical sensing. This work contributes to advancing sustainable and efficient graphene synthesis while exploring its promising properties for practical applications.

Methods of obtaining graphene

Graphene was first obtained at the beginning of the 21st century, and since then various methods have been developed for its synthesis. This variety is explained by the natural layered structure of graphite. A large number of methods is based on the idea of separating graphite layers. They are considered relatively cheap, productive and available in almost all laboratories. Another group of graphene synthesis methods is based on the concept of creating graphene sheets from individual carbon atoms. These methods are technologically more complex and require appropriate specialized equipment. Due to the wide range of graphene synthesis methods and their availability, researchers from all over the world can conduct experiments with this unique material in various scientific fields. This makes graphene an extremely promising object for further scientific research.

Research on the important properties of Graphene/AgNWs composites

Nano-material refers to small particles with a size within 100nm. It has received widespread attention from many industries because of its different performances of the light, electricity, heat and other industries that are different from conventional materials. In recent years, new nanomaterials such as AgNWs and graphene have attracted considerable attention worldwide due to their extremely high electrical conductivity and light transmission. However, AgNWs are less stable and graphene is less homogeneous in terms of resistance; thus, improving the performance by hybridizing the two composites has become a major research goal. In this paper, the synthesis methods of graphene and graphene/AgNWs composites are presented, and various properties of the composites, such as electrical conductivity, flexibility, and stress-strain capability, are also presented. The comparative analysis of these properties concludes that the excellent properties of graphene/silver nanowire composites have great potential for development and still need to be explored continuously.

Green fabrication of unoxidized graphene by combination of frozen dispersion and multimode microwave thermal shock

Next-generation electronic materials must be produced and used sustainably. Nanocarbon materials have attracted much attention as next-generation materials because they have excellent properties and can be made from readily available and inexpensive raw materials. Among them, graphene is highly expected as a material that realizes high performance and energy saving in electric devices. It has excellent properties such as high electrical conductivity, high strength, and light weight. However, the current synthesis method for graphene requires the use of toxic chemicals such as strong oxidants and a large amount of energy consumption due to use of high vacuum and high temperature. Those requirements increases the environmental impact and cost. Therefore, a simple, environmentally friendly, inexpensive, and innovative process is required for the practical use of graphene. We have developed a novel process with a new mechanism using inexpensive and safe raw materials such as graphite, ice, and simple organic solvents and general equipment such as a microwave oven. The combination of the thermal expansion properties of graphite and the selective heating properties of microwaves created the new process. This paper shows that graphene synthesis can be achieved easily and cost-effectively using familiar equipment and materials by combining fundamental physical properties and phenomena.

Strategies and Applications of Graphene and Its Derivatives-Based Electrochemical Sensors in Cancer Diagnosis.

Graphene is an emerging nanomaterial increasingly being used in electrochemical biosensing applications owing to its high surface area, excellent conductivity, ease of functionalization, and superior electrocatalytic properties compared to other carbon-based electrodes and nanomaterials, enabling faster electron transfer kinetics and higher sensitivity. Graphene electrochemical biosensors may have the potential to enable the rapid, sensitive, and low-cost detection of cancer biomarkers. This paper reviews early-stage research and proof-of-concept studies on the development of graphene electrochemical biosensors for potential future cancer diagnostic applications. Various graphene synthesis methods are outlined along with common functionalization approaches using polymers, biomolecules, nanomaterials, and synthetic chemistry to facilitate the immobilization of recognition elements and improve performance. Major sensor configurations including graphene field-effect transistors, graphene modified electrodes and nanocomposites, and 3D graphene networks are highlighted along with their principles of operation, advantages, and biosensing capabilities. Strategies for the immobilization of biorecognition elements like antibodies, aptamers, peptides, and DNA/RNA probes onto graphene platforms to impart target specificity are summarized. The use of nanomaterial labels, hybrid nanocomposites with graphene, and chemical modification for signal enhancement are also discussed. Examples are provided to illustrate applications for the sensitive electrochemical detection of a broad range of cancer biomarkers including proteins, circulating tumor cells, DNA mutations, non-coding RNAs like miRNA, metabolites, and glycoproteins. Current challenges and future opportunities are elucidated to guide ongoing efforts towards transitioning graphene biosensors from promising research lab tools into mainstream clinical practice. Continued research addressing issues with reproducibility, stability, selectivity, integration, clinical validation, and regulatory approval could enable wider adoption. Overall, graphene electrochemical biosensors present powerful and versatile platforms for cancer diagnosis at the point of care.

Scalable Production of 2D Material Heterostructure Textiles for High-Performance Wearable Supercapacitors.

Wearable electronic textiles (e-textiles) have emerged as a promising platform for seamless integration of electronic devices into everyday life, enabling nonintrusive monitoring of human health. However, the development of efficient, flexible, and scalable energy storage solutions remains a significant challenge for powering such devices. Here, we address this challenge by leveraging the distinct properties of two-dimensional (2D) material based heterostructures to enhance the performance of wearable textile supercapacitors. We report a highly scalable and controllable synthesis method for graphene and molybdenum disulfide (MoS2) through a microfluidization technique. Subsequently, we employ an ultrafast and industry-scale hierarchical deposition approach using a pad-dry method to fabricate 2D heterostructure based textiles with various configurations suitable for wearable e-textiles applications. Comparative analyses reveal the superior performance of wearable textile supercapacitors based on 2D material heterostructures, demonstrating excellent areal capacitance (∼105.08 mF cm-2), high power density (∼1604.274 μW cm-2) and energy density (∼58.377 μWh cm-2), and outstanding capacitive retention (∼100% after 1000 cycles). Our findings highlight the pivotal role of 2D material based heterostructures in addressing the challenges of performance and scalability in wearable energy storage devices, facilitating large-scale production of high-performance wearable supercapacitors.

Advancements in Plasma-Enhanced Chemical Vapor Deposition for Producing Vertical Graphene Nanowalls.

In recent years, vertical graphene nanowalls (VGNWs) have gained significant attention due to their exceptional properties, including their high specific surface area, excellent electrical conductivity, scalability, and compatibility with transition metal compounds. These attributes position VGNWs as a compelling choice for various applications, such as energy storage, catalysis, and sensing, driving interest in their integration into next-generation commercial graphene-based devices. Among the diverse graphene synthesis methods, plasma-enhanced chemical vapor deposition (PECVD) stands out for its ability to create large-scale graphene films and VGNWs on diverse substrates. However, despite progress in optimizing the growth conditions to achieve micrometer-sized graphene nanowalls, a comprehensive understanding of the underlying physicochemical mechanisms that govern nanostructure formation remains elusive. Specifically, a deeper exploration of nanometric-level phenomena like nucleation, carbon precursor adsorption, and adatom surface diffusion is crucial for gaining precise control over the growth process. Hydrogen's dual role as a co-catalyst and etchant in VGNW growth requires further investigation. This review aims to fill the knowledge gaps by investigating VGNW nucleation and growth using PECVD, with a focus on the impact of the temperature on the growth ratio and nucleation density across a broad temperature range. By providing insights into the PECVD process, this review aims to optimize the growth conditions for tailoring VGNW properties, facilitating applications in the fields of energy storage, catalysis, and sensing.

Two-Step Thermal Transformation of Multilayer Graphene Using Polymeric Carbon Source Assisted by Physical Vapor Deposited Copper.

Direct in situ growth of graphene on dielectric substrates is a reliable method for overcoming the challenges of complex physical transfer operations, graphene performance degradation, and compatibility with graphene-based semiconductor devices. A transfer-free graphene synthesis based on a controllable and low-cost polymeric carbon source is a promising approach for achieving this process. In this paper, we report a two-step thermal transformation method for the copper-assisted synthesis of transfer-free multilayer graphene. Firstly, we obtained high-quality polymethyl methacrylate (PMMA) film on a 300 nm SiO2/Si substrate using a well-established spin-coating process. The complete thermal decomposition loss of PMMA film was effectively avoided by introducing a copper clad layer. After the first thermal transformation process, flat, clean, and high-quality amorphous carbon films were obtained. Next, the in situ obtained amorphous carbon layer underwent a second copper sputtering and thermal transformation process, which resulted in the formation of a final, large-sized, and highly uniform transfer-free multilayer graphene film on the surface of the dielectric substrate. Multi-scale characterization results show that the specimens underwent different microstructural evolution processes based on different mechanisms during the two thermal transformations. The two-step thermal transformation method is compatible with the current semiconductor process and introduces a low-cost and structurally controllable polymeric carbon source into the production of transfer-free graphene. The catalytic protection of the copper layer provides a new direction for accelerating the application of graphene in the field of direct integration of semiconductor devices.

Ultrafast synthesis of novel coal-based graphene and its anticorrosion properties of epoxy/graphene nanocomposite coatings

Graphene has a wide range of applications in anti-corrosion coatings due to its excellent barrier, shielding, and mechanical properties. However, traditional graphene synthesis methods, including the production of graphene oxide (GO) using Homer's method and then its reduction in the form of reduced graphene oxide (rGO) are time-consuming, energy-consuming, and environmentally polluting, which limits their application in anti-corrosion coatings. This study leveraged the capabilities of flash Joule heating (FJH) to synthesize flash coal-based graphene (FCBG) from Taixi anthracite (TA) within 200 ms without pretreatments or chemical reagents. The FJH had the advantages of low energy consumption and being environmentally friendly. Compared with the rGO, the FCBG prepared by FJH was characterized by fewer defects, larger carbon sheets, and a turbostratic structure. Moreover, carbon steel Q235 was used as the substrate to prepare anti-corrosion coatings by mixing FCBG at different flash voltages with epoxy resin (EP). Based on this, the electrochemical performance of different coatings was compared before and after salt spray corrosion. The results demonstrated that the FCBG composite anti-corrosion coating (EP/FCBG190) prepared using EP and FCBG synthesized at 190 V in the FJH, displayed stronger corrosion resistance than the EP and rGO composite coating (EP/rGO). The FJH synthesis process provides a feasible route for improving the synthesis process of the anti-corrosion coatings and the high value-added utilization of coal.

An electrochemical approach for bulk production of reduced graphene oxide from graphite oxide followed by thermal reduction

A high-quality, bulk synthesis of graphene that is inexpensive, and environmentally safe is highly desired because of the broad range of applications. In comparison to the chemical vapor deposition (CVD) method, epitaxial growth on silicon carbide, etc., the electrochemical approach is thought to be the most straightforward and eco-friendly way for the cost-effective bulk production of graphene from graphite. Moreover, the thermal reduction method appears to be a particularly cost-effective way to eliminate oxygen-containing functional groups when compared to chemical reduction. The yield of graphene is also impacted by the choice of cathode low-cost, which is extremely important and played a critical role during the synthesis process. In this work, we demonstrate a green, eco-friendly, and cost-effective electrochemical method for the synthesis of reduced graphene oxide (RGO) followed by thermal reduction. To accomplish electrochemical exfoliation for the graphene synthesis, a constant DC power of 65[Formula: see text]W ([Formula: see text][Formula: see text]V and [Formula: see text][Formula: see text]amp) has been supplied within an electrolytic cell that contains 2[Formula: see text]M of sulphuric acid as an electrolytic solution. The aluminium has been utilized as a cathode in place of the platinum, carbon cathode, etc. Moreover, to prepare the electrolytic solution and for the sonication process, sterilized water has been used in place of DI (deionized water). Thereafter, previously oxidized graphite oxide has been thermally reduced at a temperature of [Formula: see text]C. The phase, crystallinity, and interatomic distance were investigated using X-Ray diffraction (XRD) analysis. X-Ray data show that the RGO crystal structure has been recovered following high-temperature annealing. The diffraction peak seems to be at [Formula: see text] with an interplaner distance of 3.48[Formula: see text]Å. The intensity of the defect, as measured by the [Formula: see text] ratio (intensity ratio), was analyzed using Raman spectra, and the result of that investigation was found to be 0.196. The findings of the Raman study unambiguously reveal that the severity of the defects is judged to be on the lower end of the spectrum. The surface texture, microstructure, and elemental analysis were performed using atomic force microscopy (AFM), Field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), and EDX analysis. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to determine the number of oxygen-containing functional groups that existed in the RGO sample and their thermostability. The results of FTIR and TGA analysis clearly demonstrate that the reduction temperature has a major role in determining the proportion of oxygen that is present in the graphene. This study presents a large-scale, cost-effective, and eco-friendly graphene synthesis method for industrial applications.

Recent advances on the development of graphene‐based field‐effect transistors, electrochemical biosensors and electrochemiluminescence biosensors

AbstractGraphene, a honeycomb lattice of carbon material with single‐atom‐layer structure, demonstrates extraordinary mechanical, thermal, chemical and electronic properties. Thus, it has sparked tremendous interests in various fields, such as energy storage and conversion devices, field‐effect transistors (FET), chemical sensors and biosensors. In this review, we will first focus on the synthesis method of graphene and the fabrication strategy of graphene‐based materials. Subsequently, the construction of graphene‐based biosensors are introduced, in which three kinds of biosensors are discussed in details, including the FET, electrochemical biosensors and electrochemiluminescence (ECL) biosensors. The performances of the state‐of‐the‐art biosensors on the detection of biomolecules are also displayed. Finally, we also highlight some critical challenges remain to be solved and the development in this field for further research.

State-of-the-Art Graphene Synthesis Methods and Environmental Concerns

Graphene, a 2D sp2 hybridized carbon sheet consisting of a honeycomb network, is the building block of graphite. Since its discovery in 2004, graphene’s exceptional electronic and mechanical properties have peaked interest in various applications. However, the inability to mass produce high-quality graphene affordably currently limits the practical application of the material. Researchers are continuously working on advancing graphene synthesis methods to alleviate these limitations. Therefore, this review looks at the overview of established graphene synthesis methods and characterization techniques, and then highlights an in-depth review of graphene production through flash joule heating. The environmental concerns related to graphene synthesis are also presented in this review paper.

A review on appropriate graphene synthesis methods for diverse applications

After exfoliation of graphite and discovered graphene in 2004 by Novoselov and Geim, the attention of graphene by the global scientific community enhanced progressively as a multifunctional wonder material in the world due to its unique extraordinary properties. Numerous methods apart from the discovered method have been investigated to synthesize the graphene in mass scale for variety of applications. Consequently, we believe that an adequate knowledge is necessary to choose a proper method of synthesis for a particular application. The main objective of the present review is to summarize the feasible methods followed in synthesis of graphene, discussing their properties, applications, advantages, and disadvantages for future prospects.

Ultra‐High Loading of Coal‐Derived Flash Graphene Additives in Epoxy Composites

AbstractGraphene has proved to be an exceptional reinforcing additive for composites, but the high cost of its synthesis has largely prevented its addition on industrial scales. Flash Joule heating provides a rapid, bulk‐scale method for graphene synthesis from coal materials, such as metallurgical coke (MC), into metallurgical coke‐derived flash graphene (MCFG). Here, this work investigates the properties of graphene‐epoxy composites in a higher nanofiller content regime than has previously been reported in literature. Composites with 20 to 50 wt% loading of MCFG are prepared by combining MCFG with diglycidyl ether bisphenol A epoxy precursor (DGEBA) and 1,5‐diamino‐2‐methylpentane. With a 1:2 ratio of MCFG:DGEBA, the Young's modulus increases by 92% and with a 1:3 ratio, hardness increases by 140%. At a 1:4 ratio of MCFG:DGEBA, compressive strength and maximum strain increase by 145% and 61%, respectively. At a 1:3 ratio of MCFG:DGEBA, toughness increases by 496%. Finally, at a 1:1 ratio of MCFG:DGEBA, GHG emissions, water consumption, and energy consumption are reduced by 33%, 47%, and 34%, respectively. As the cost of FG plummets, since it can be produced from very low cost materials like MC, in milliseconds with no solvent or water, the prospects are promising for its high‐loading use in composites.

Biyokütlelerden Karbon Bazlı Nanomalzemelerin Sentezi Üzerine Kısa Bir Bakış

Biomass from agricultural waste offers an abundant, natural and affordable carbon source for the synthesis of value-added carbonaceous materials. The conversion of these agricultural wastes into nanoscale products relies on the development of environmentally friendly, affordable, simple and scalable new synthesis methods for commercial production of graphene-type nanomaterials. However, all agricultural waste acts as a carbonaceous product required for GO production. Based on this, in this study, new biomass materials and economical approaches were proposed to prepare GO. In addition, the advantages and disadvantages of graphene synthesis methods were discussed and green nanotechnology was examined. Some studies on the synthesis of carbon-based nanomaterials from biomass were examined and the place of graphene in health applications was investigated. How lignocellulosic biomass was converted into carbon-based nanomaterials was investigated and its mechanism was discussed.

A Novel Sustainable Process for Multilayer Graphene Synthesis Using CO2 from Ambient Air.

Graphene produced by different methods can present varying physicochemical properties and quality, resulting in a wide range of applications. The implementation of a novel method to synthesize graphene requires characterizations to determine the relevant physicochemical and functional properties for its tailored application. We present a novel method for multilayer graphene synthesis using atmospheric carbon dioxide with characterization. Synthesis begins with carbon dioxide sequestered from air by monoethanolamine dissolution and released into an enclosed vessel. Magnesium is ignited in the presence of the concentrated carbon dioxide, resulting in the formation of graphene flakes. These flakes are separated and enhanced by washing with hydrochloric acid and exfoliation by ammonium sulfate, which is then cycled through a tumble blender and filtrated. Raman spectroscopic characterization, FTIR spectroscopic characterization, XPS spectroscopic characterization, SEM imaging, and TEM imaging indicated that the graphene has fifteen layers with some remnant oxygen-possessing and nitrogen-possessing functional groups. The multilayer graphene flake possessed particle sizes ranging from 2 µm to 80 µm in diameter. BET analysis measured the surface area of the multilayer graphene particles as 330 m2/g, and the pore size distribution indicated about 51% of the pores as having diameters from 0.8 nm to 5 nm. This study demonstrates a novel and scalable method to synthesize multilayer graphene using CO2 from ambient air at 1 g/kWh electricity, potentially allowing for multilayer graphene production by the ton. The approach creates opportunities to synthesize multilayer graphene particles with defined properties through a careful control of the synthesis parameters for tailored applications.

Graphene-Based Polymer Composites for Flexible Electronic Applications.

Graphene-based nanomaterials have gained a lot of interest over the last years in flexible electronics due to their exceptional electrical, mechanical, and optoelectronic properties, as well as their potential of surface modification. Their flexibility and processability make them suitable for electronic devices that require bending, folding, and stretching, which cannot be fulfilled by conventional electronics. These nanomaterials can be assembled with various types of organic materials, including polymers, and biomolecules, to generate a variety of nanocomposites with greater stretchability and healability, higher stiffness, electrical conductivity, and exceptional thermal stability for flexible lighting and display technologies. This article summarizes the main characteristics and synthesis methods of graphene, its oxidized form graphene oxide (GO), and reduced GO derivative, as well as their corresponding polymeric composites, and provides a brief overview about some recent examples of these nanocomposites in flexible electronic applications, including electrodes for solar cells and supercapacitors, electronic textiles, and transistors.

Insights into forming behavior and CO2 adsorption properties of graphene from Sargassum horneri by Fe(NO3)3/KOH activation

AbstractBACKGROUNDMacroalgae biomass as a graphene source shows great potential at large scale in an energy shortage era. To achieve a more moderate and economic graphene synthesis method, porous graphenes were synthesized using Sargassum horneri as precursor, in combination with Fe(NO3)3 and KOH composite.RESULTSThe addition of 10 wt% Fe(NO3)3 obviously accelerated KOH activation and decreased KOH loading and reaction temperature. Meanwhile, the graphene synthesized by Fe(NO3)3/KOH had better regeneration performance than that activated merely by KOH, even under more moderate thermal condition. The porous graphene displayed high specific surface area (~2311 m2 g−1) and exhibited good CO2 uptake capacity (~4.39 mmol g−1) at 30 °C and 1 bar. The CO2 adsorption rate equations of the graphene were consistent with the intraparticle diffusion model, indicating that CO2 adsorption was mainly controlled by the pore structure and additionally influenced by the chemical functional groups.CONCLUSIONThe present work focuses on the high value‐added comprehensive utilization of macroalgae, which not only has important significance for on‐scale preparation of bio‐originated graphene and CO2 adsorption, but also has positive benefits for macroalgae resource development. © 2022 Society of Chemical Industry (SCI).