Applications Of Graphene-based Materials Research Articles

Influence of multilayers Bernal and Rhombohedral graphene obtained by green chemistry on the acceleration in the germination process of tomato seeds

The environmental ramifications stemming from the application of graphene-based materials have sparked significant interest in recent years. This study delved into assessing the influence of multilayer graphene, specifically focusing on the Bernal (2H) and Rhombohedral (3R) phases, on the germination process of tomato (Solanum lycopersicum) seeds. Multilayers Bernal-Rhombohedral Graphene (MBRG) were synthesized employing green chemistry principles, utilizing the ultrasonication technique operating at 40 kHz within a deionized water solution. Systematic characterization of the phases was conducted via X-ray diffraction, Raman Spectroscopy, TEM, and conductivity measurements. Subsequent administration of MBRG at concentrations ranging from 10 to 500 mgL−1 on tomato seeds revealed an expedited germination process, achieving completion within 3 days. Noteworthy enhancements were observed, including a 12 % absolute increase in germination, a 3 % rise in relative root growth, and a 9 % elevation in the germination index compared to the control. Moreover, a discernible augmentation in root length was evident with escalating concentrations of MBRG, peaking at 50 mgL−1, albeit exhibiting a slight decrement at 500 mgL−1. Additionally, the antioxidant activities of root extracts were assessed across various MBRG concentrations, demonstrating no significant alterations. The outcomes posit that MBRG compositions, comprising 60.44 % (2H) and 39.55 % (3R) phases at specific concentrations, hold promise as a viable additive for expediting early seed germination, thereby presenting a potential sustainable solution in agricultural contexts.

Development and application of graphene-based materials in memristors

Development and application of graphene-based materials in memristors

An overview of contemporary developments and the application of graphene-based materials in anticorrosive coatings.

Although graphene and graphene-based materials (GBMs) offer a wide range of possible applications, interest in their use as barrier layers or as reinforcements in coatings for the mitigation of corrosion has grown during the past decade. Because of its unique two-dimensional nanostructure and exceptional physicochemical characteristics, graphene has gotten a lot of attention as an anti-corrosion material. This enthusiasm is largely driven by the requirement to integrate more features, improve anti-corrosion effectiveness, and eventually prolong the service duration of metallic components. As barriers against metal corrosion, graphene nanosheets can be applied singly or in combination to create thin films, layered frameworks, or composites. Concurrently, over the past few years, significant advancements have been made in the establishment of scalable production methods for graphene and materials based on graphene. Since there is currently a wide variety of graphene material with various morphologies and characteristics, it is even more important that the production approach and the intended application be properly matched. This review gathers the most recent data and aims to give the reader a comprehensive overview of the most recent developments in the use of graphene and GBMs in various anti-corrosion strategies. The structure-property correlation and anticorrosion techniques in these systems are given special consideration. The current article offers a critical examination of this topic as well, stressing the areas that require more research.

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

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

Assessment of genotoxicity induced by subchronic exposure to graphene in HaCaT human skin cell line

The applications of graphene-based materials (GBMs) and their processing involve prolonged contact with cellular barriers such as human skin. Even though the potential cytotoxicity of graphene has been studied in recent years, the impact of long-term graphene exposure has rarely been explored. We tested in the HaCaT epithelial cells, in vitro, the effect of subchronic treatments with sublethal doses of four different, well-characterized GBMs, two commercial graphene oxides (GO) and two few-layer graphenes (FLG). Cells were exposed weekly to low doses of the GBMs for 14 days, 30 days, 3 months, and 6 months. GBMs-cells uptake was assessed by confocal microscopy. Cell death and cell cycle were determined by fluorescence microscopy and cytometry. DNA damage was measured by comet assay and γ-H2AX staining, followed by the determination of p-p53 and p-ATR by immunolabeling. Subchronic exposure to different GBMs at noncytotoxic doses has potential genotoxic effects on HaCaT epithelial cells that can be recovered depending on the GBM and exposure time. Specifically, GO-induced genotoxicity can be detected after 14 and 30 days from treatment. At this time, FLG appears less genotoxic than GO, and cells can recover more quickly when genotoxic pressure disappears after some days of removal of the GBM. Long-term exposure, 3 and 6 months, to different GBMs induces permanent, nonreversible, genotoxic damage comparable to the exerted by arsenite. This should be considered for the production and future applications of GBMs in scenarios where low concentrations of the material interact chronically with epithelial barriers.

An overview of the application of graphene-based materials in anticorrosive coatings

• Anti-corrosion performance of graphene and graphene based material coatings is reviewed. • Chemically modified graphene oxide emerged as new class of corrosion inhibitors. • Future development directions for graphene anti-corrosive coatings are anticipated. Graphene-based materials (GBMs) have an extensive range of potential uses, but over past ten years, interest in their usage as barrier layer or as reinforcements in coatings for corrosion prevention has developed. This review compiles the most recent information and seeks to provide authors with a broad synopsis of the most contemporary progresses in the application of GBMs in various anti-corrosion techniques.

Effects of TiO2-Modified RGO Composites on the Mechanical and Durability Properties of Ordinary Portland Cement Mortars

Various applications of graphene-based materials in construction are an alternative to improve the properties of ordinary Portland cement (OPC)-based binders. This paper used a titanium dioxide in situ intercalation method to enhance the dispersibility of reduced graphene oxide (RGO) and then explored the effects of the incorporation of the obtained TiO2–RGO composite and RGO on the mechanical and durability-related properties of the OPC-based binders. Experimental results showed that TiO2 was successfully intercalated into the RGO layers and could improve the dispersion of RGO in water or synthesized OPC pore solution significantly, probably due to the greater spacing between each RGO layer. Besides, a proper amount of TiO2-modified RGO composite (0.03 wt % in this study) could elevate the mechanical strengths of OPC mortars, evidenced by a large increment of 24.78% and up to 34.94% in the compressive strength and flexural strength, respectively. The TiO2–RGO composite led to higher flexural-to-compressive strength ratios with the given dosages (0.01–0.05 wt %), implying a higher fractural toughness. Moreover, the resistance of the enhanced OPC-based mortars toward chloride attacks and freeze–thaw cycles was significantly improved. Based on the microstructural analyses including scanning electron microscopy and X-ray diffraction results, it is found that the modified RGO could to some extent promote the hydration of OPC and densify the overall microstructure of bulk specimens, leading to enhanced mechanical and durability properties. Compared to normal RGO, the TiO2–RGO composite was more effective in enhancing the properties of OPC mortars, due in large part to its better dispersion state.

Graphene-Oxide-Enriched Biomaterials: A Focus on Osteo and Chondroinductive Properties and Immunomodulation.

Due to its exceptional physical properties, such as high electronic conductivity, good thermal stability, excellent mechanical strength, and chemical versatility, graphene has sparked a lot of interest in the scientific community for various applications. It has therefore been employed as an antibacterial agent, in photothermal therapy (PTT) and biosensors, in gene delivery systems, and in tissue engineering for regenerative purposes. Since it was first discovered in 1947, different graphene derivatives have been synthetized from pristine graphene. The most adaptable derivate is graphene oxide (GO). Owing to different functional groups, the amphiphilic structure of GO can interact with cells and exogenous or endogenous growth/differentiation factors, allowing cell adhesion, growth, and differentiation. When GO is used as a coating for scaffolds and nanomaterials, it has been found to enhance bone, chondrogenic, cardiac, neuronal, and skin regeneration. This review focuses on the applications of graphene-based materials, in particular GO, as a coating for scaffolds in bone and chondrogenic tissue engineering and summarizes the most recent findings. Moreover, novel developments on the immunomodulatory properties of GO are reported.

Preparation, Properties, and Application of Graphene-Based Materials in Tissue Engineering Scaffolds.

Tissue engineering has a great application prospect as an effective treatment for tissue and organ injury, functional reduction, or loss. Bioactive tissues are reconstructed and damaged organs are repaired by the three elements, including cells, scaffold materials, and growth factors. Graphene-based composites can be used as reinforcing auxiliary materials for tissue scaffold preparation because of their large specific surface area, and good mechanical support. Tissue engineering scaffolds with graphene-based composites have been widely studied. Part of research have focused on the application of graphene-based composites in single tissue engineering. The basic principles of graphene materials used in tissue engineering are summarized in some research. Some studies emphasized the key problems and solutions urgently needed to be solved in the development of tissue engineering and discussed their application prospect. Some related studies mainly focused on the conductivity of graphene and discussed the application of electroactive scaffolds in tissue engineering. In this review, the composite materials for preparing tissue engineering scaffolds are briefly described, which emphasizes the preparation methods, biological properties, and practical applications of graphene-based composite scaffolds. The synthetic techniques, with stressing solvent casting, electrospinning, and three-dimensional printing, are introduced in detail. The mechanical, cell-oriented, and biocompatible properties of graphene-based composite scaffolds in tissue engineering are analyzed and summarized. Their applications in bone tissue engineering, nerve tissue engineering, cardiovascular tissue engineering, and other tissue engineering are summarized systematically. In addition, this work also looks forward to the difficulties and challenges in the future research, providing some references for the follow-up research of graphene-based composites in tissue engineering scaffolds. Impact statement Regeneration and repair of tissue and organ injury has become a new research hotspot in recent years. Tissue engineering scaffolds prepared with graphene-based materials have good biocompatibility, excellent mechanical properties, and strong cell orientation, which can fully induce the proliferation and differentiation of seed cells. This review briefly describes the basic materials for the preparation of tissue engineering scaffolds, and focuses on the preparation, performance, and application of graphene-based materials in tissue engineering, providing sufficient understanding of graphene applied in regenerative medicine.

Applications of Graphene-Based Materials in Sensors: A Review.

With the research and the development of graphene-based materials, new sensors based on graphene compound materials are of great significance to scientific research and the consumer market. However, in the past ten years, due to the requirements of sensor accuracy, reliability, and durability, the development of new graphene sensors still faces many challenges in the future. Due to the special structure of graphene, the obtained characteristics can meet the requirements of high-performance sensors. Therefore, graphene materials have been applied in many innovative sensor materials in recent years. This paper introduces the important role and specific examples of sensors based on graphene and its base materials in biomedicine, photoelectrochemistry, flexible pressure, and other fields in recent years, and it puts forward the difficulties encountered in the application of graphene materials in sensors. Finally, the development direction of graphene sensors has been prospected. For the past two years of the COVID-19 epidemic, the detection of the virus sensor has been investigated. These new graphene sensors can complete signal detection based on accuracy and reliability, which provides a reference for researchers to select and manufacture sensor materials.

Graphene-Based Nanomaterials as Drug Delivery Carriers.

Graphene and graphene-based materials have been attracted in the past few years for biomedical applications due to their physicochemical and biological properties such as large surface area, chemical and mechanical stability, excellent conductivity, and good biocompatibility. Graphene-based materials not only surface modified graphene-based materials like graphene oxide (GO) or reduced graphene oxide (rGO) but also other structural forms like fullerene, carbon nanotubes, and graphite have been applied to advanced drug delivery systems. In this chapter, we review on the application of graphene-based materials in the drug delivery system with their physicochemical properties, methods for the preparation of graphene-based carriers, followed by analysis about their biodistribution and biosafety whether they are suitable as drug delivery carriers.

A Review on the Production Methods and Applications of Graphene-Based Materials.

Graphene-based materials in the form of fibres, fabrics, films, and composite materials are the most widely investigated research domains because of their remarkable physicochemical and thermomechanical properties. In this era of scientific advancement, graphene has built the foundation of a new horizon of possibilities and received tremendous research focus in several application areas such as aerospace, energy, transportation, healthcare, agriculture, wastewater management, and wearable technology. Although graphene has been found to provide exceptional results in every application field, a massive proportion of research is still underway to configure required parameters to ensure the best possible outcomes from graphene-based materials. Until now, several review articles have been published to summarise the excellence of graphene and its derivatives, which focused mainly on a single application area of graphene. However, no single review is found to comprehensively study most used fabrication processes of graphene-based materials including their diversified and potential application areas. To address this genuine gap and ensure wider support for the upcoming research and investigations of this excellent material, this review aims to provide a snapshot of most used fabrication methods of graphene-based materials in the form of pure and composite fibres, graphene-based composite materials conjugated with polymers, and fibres. This study also provides a clear perspective of large-scale production feasibility and application areas of graphene-based materials in all forms.

Rational Design of Self-Supported CuO x -Decorated Composite Films as an Efficient and Easy-Recycling Catalyst for Styrene Oxidation.

The applications of graphene-based materials in catalysis are limited by their strong tendency to aggregate, which may lead to a decrease in active sites. Herein, we propose a facile and controllable strategy to fabricate a series of heterogeneous catalysts with a unique nanostructure wherein CuOx-decorated reduced graphene oxide (rGO) sheets are incorporated into a solid matrix composed of poly(vinylpyrrolidone) (PVP) and carboxymethyl cellulose (CMC). The resultant materials are self-supported films and could be directly used as catalysts for the liquid-phase oxidation of styrene without the requirement for extra substrates. The employment of PVP-CMC (PC) as the support for CuOx-decorated rGO sheets successfully inhibits their aggregation. Benefiting from the dispersion of copper species, these films exhibit good catalytic activity and recyclability under mild reaction conditions. Especially, they can be conveniently removed from the reaction mixture by tweezers due to their structural stability. For catalyzing multiple reactions with high efficiency and facile recyclability, this study offers a universal strategy to design heterogeneous catalysts based on graphene materials and provides a promising platform.

Theoretical calculation boosting the chemical vapor deposition growth of graphene film

Chemical vapor deposition (CVD) is a promising method for the mass production of high-quality graphene films, and great progress has been made over the last decade. Currently, the CVD growth of graphene is being pushed to achieve further advancements, such as super-clean, ultra-flat, and defect-free materials, as well as controlling the layer, stacking order, and doping level during large-scale preparation. The production of high-quality graphene by CVD relies on an in-depth knowledge of the growth mechanisms, in which theoretical calculations play a crucial role in providing valuable insights into the energy-, time-, and scale-dependent processes occurring during high-temperature growth. Here, we focus on the theoretical calculations and discuss the recent progress and challenges that need to be overcome to achieve controllable growth of high-quality graphene films on transition-metal substrates. Furthermore, we present some state-of-the-art graphene-related structures with novel properties, which are expected to enable new applications of graphene-based materials.

Interaction with teichoic acids contributes to highly effective antibacterial activity of graphene oxide on Gram-positive bacteria

Graphene oxide (GO) has high-efficient antibacterial activity to diverse pathogenic bacteria. However, the detailed antibacterial mechanism of GO is not fully clear. Herein the antibacterial properties of GO against model Gram-positive (Gram+) (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative (Gram−) bacteria (Pseudomonas aeruginosa and Escherichia coli) were compared by plate count method. Results showed that 4 mg/L of GO induced the mortality of Gram+ and Gram− bacteria by > 99% and < 25%, respectively. GO had greater adsorption affinity to teichoic acids, the unique components existing in the cell wall of Gram+ bacteria, mainly via π−π interaction. The adsorption efficiency of teichoic acids was 27 times higher than that of peptidoglycan when they were simultaneously exposed to 100 mg/L GO. The superior adsorption of teichoic acids onto GO increased one order of magnitude of atlA expression, the autolysin related gene. As a result, these accelerated bacterial death by hydrolyzing peptidoglycan in cell walls. Exogenous addition of 50 mg/L teichoic acids could impair 4–5 fold of antibacterial activity of GO against S. aureus. These new findings illuminate the antibacterial mechanism of GO against Gram+ bacteria, which paves the way for the further application of graphene-based materials in water disinfection and pathogen control.

Sustainable Catalytic Processes Driven by Graphene-Based Materials

In the recent two decades, graphene-based materials have achieved great successes in catalytic processes towards sustainable production of chemicals, fuels and protection of the environment. In graphene, the carbon atoms are packed into a well-defined sp2-hybridized honeycomb lattice, and can be further constructed into other dimensional allotropes such as fullerene, carbon nanotubes, and aerogels. Graphene-based materials possess appealing optical, thermal, and electronic properties, and the graphitic structure is resistant to extreme conditions. Therefore, the green nature and robust framework make the graphene-based materials highly favourable for chemical reactions. More importantly, the open structure of graphene affords a platform to host a diversity of functional groups, dopants, and structural defects, which have been demonstrated to play crucial roles in catalytic processes. In this perspective, we introduced the potential active sites of graphene in green catalysis and showcased the marriage of metal-free carbon materials in chemical synthesis, catalytic oxidation, and environmental remediation. Future research directions are also highlighted in mechanistic investigation and applications of graphene-based materials in other promising catalytic systems.

Improved performance of perovskite solar cells using conjugated polymer-graphene oxide as the passivation material

Organic-inorganic hybrid perovskite solar cells (PSCs) have achieved power conversion efficiency (PCE) from 3.8% to 25.2% in recent years. However, the charge transport ability of the transporting layers and the quality of crystalline films limit further development of PSCs. To fabricate highly efficient PSCs, effective charge transport to electrodes through transporting layers is a necessary requirement. Suitable interface engineering is very critical because it can not only benefit the charge extraction and transport, but also effectively passivate the traps on the surface and grain boundary of the perovskite. It has been shown that the passivation layer for the perovskite plays a vital role in the performance of PSCs. The close fit between the charge transport layer and the perovskite layer is required to reduce the interfacial recombination and accelerate the carrier extraction and collection. Besides, the appropriate passivation layer has a potential impact on the crystallization and the morphology of the perovskite film. To achieve high-performance devices, it is crucial to design an effective passivation layer with appropriate nanomaterials. In this work, we synthesized poly[(2-methoxy,5-octoxy)1,4-phenylenevinylene] (MOPPV) on few-layer graphene oxide (GO) by in situ polymerization at room temperature. MOPPV-GO can fully combine the advantages of the two materials. The novel nanocomposite MOPPV-GO is used as the ultra-thin passivation layer of PSCs, of which the structure is ITO/TiO2/(FAPbI3) x (MAPbCl3)1– x /MOPPV-GO/spiro-OMeTAD/Ag. Since the surface morphology of the perovskite layer would affect the performance of devices significantly, the perovskite films with and without the passivation layer by atomic force microscopy is found that the MOPPV-GO can facilitate the growth of perovskite crystal with larger grains and enhance the quality of perovskite films. The root mean square roughness values of the perovskite films with and without MOPPV-GO were evaluated to be 19.87 and 25.85 nm, justifying the improvement of the surface flatness of the perovskite film with the decoration of MOPPV-GO, which would enhance the contact and carrier transport between the hole transport layer and the perovskite layer. As a result, the PSCs with MOPPV-GO exhibited considerably low hysteresis indices (0.02) and showed a short circuit current density of 23.54 mA cm–1, an open circuit voltage of 1.09 V, and a fill factor of 76.46%, corresponding to a high power conversion efficiency of 19.73%. By contrast, the control PSCs without MOPPV-GO showed a high hysteresis index of 0.18, with a poor power conversion efficiency of 16.42%. Meanwhile, it is shown that the EQE curve of MOPPV-GO modified PSC is higher than that of unmodified devices, which is consistent with the experimental results of J-V curve. The steady-state power output of various devices in ambient conditions under continuous AM 1.5G illumination was tested, which shows excellent stability of the PSC with MOPPV-GO during the period of 1000 s, indicating the positive contribution of MOPPV-GO interlayer to the stability. This work could provide a new idea for the synthesis and application of graphene-based materials in solar cells.

Electric Power Generation through the Direct Interaction of Pristine Graphene-Oxide with Water Molecules.

Converting ubiquitous environmental energy into electric power holds tremendous social and financial interests. Traditional energy harvesters and converters are limited by the specific materials and complex configuration of devices. Herein, it is presented that electric power can be directly produced from pristine graphene oxide (GO) without any pretreatment or additives once encountering the water vapor, which will generate an open-circuit-voltage of up to 0.4-0.7 V and a short-circuit-current-density of 2-25 µA cm-2 on a single piece of GO film. This phenomenon results from the directional movement of charged hydrogen ions through the GO film. The present work demonstrates and provides an extremely simple method for electric energy generation, which offers more applications of graphene-based materials in green energy converting field.

Application of graphene-based materials in water purification: from the nanoscale to specific devices

The synthesis, multilevel structural features, adsorption performance and environmental applications of graphene nanosheets and 2D/3D graphene-based macrostructure material were summarized.

Flexible Graphene-Based Wearable Gas and Chemical Sensors.

Wearable electronics is expected to be one of the most active research areas in the next decade; therefore, nanomaterials possessing high carrier mobility, optical transparency, mechanical robustness and flexibility, lightweight, and environmental stability will be in immense demand. Graphene is one of the nanomaterials that fulfill all these requirements, along with other inherently unique properties and convenience to fabricate into different morphological nanostructures, from atomically thin single layers to nanoribbons. Graphene-based materials have also been investigated in sensor technologies, from chemical sensing to detection of cancer biomarkers. The progress of graphene-based flexible gas and chemical sensors in terms of material preparation, sensor fabrication, and their performance are reviewed here. The article provides a brief introduction to graphene-based materials and their potential applications in flexible and stretchable wearable electronic devices. The role of graphene in fabricating flexible gas sensors for the detection of various hazardous gases, including nitrogen dioxide (NO2), ammonia (NH3), hydrogen (H2), hydrogen sulfide (H2S), carbon dioxide (CO2), sulfur dioxide (SO2), and humidity in wearable technology, is discussed. In addition, applications of graphene-based materials are also summarized in detecting toxic heavy metal ions (Cd, Hg, Pb, Cr, Fe, Ni, Co, Cu, Ag), and volatile organic compounds (VOCs) including nitrobenzene, toluene, acetone, formaldehyde, amines, phenols, bisphenol A (BPA), explosives, chemical warfare agents, and environmental pollutants. The sensitivity, selectivity and strategies for excluding interferents are also discussed for graphene-based gas and chemical sensors. The challenges for developing future generation of flexible and stretchable sensors for wearable technology that would be usable for the Internet of Things (IoT) are also highlighted.