Graphene Oxide Nanosheets Research Articles

Carbon nanotubes perpendicularly grown on graphene oxide nanosheets derived from metal-organic frameworks: Synergistic reinforcement of poly(l-lactic acid) scaffold

The construction of the nanohybrid composed of two carbonaceous nanomaterials is a promising strategy to inhibit their aggregation, and effectively exert the advantages of their excellent mechanical properties as reinforcement for polymers. Here, carbon nanotubes (CNTs) were in situ perpendicularly growing on the surface of graphene oxide (GO) through metal-organic frameworks (MOF)-derived strategy by chemical vapor deposition (CVD), aiming to facilitate their dispersion on poly(l-lactic acid) (PLLA) bone scaffold fabricated by selective laser sintering (SLS). Specifically, GO provided nucleation sites for the growth of MOF, and worked as the templates when CNTs grew, in which MOF provided catalysts and carbon sources simultaneously. The precursor was heated to 550 °C and kept for 2 h, then heated to 900 °C and kept for 2 h before cooling. The obtained nanohybrid (GO@CNT) exhibited a superior dispersion state than the pure GO in the scaffold at the same loading, especially when the loading was 0.75 wt%. Adding 0.75 wt% GO@CNT endowed the scaffold with a remarkable increment in tensile strength and compressive strength of 13.36 MPa and 24.72 MPa with enhancement of 55.35% and 18.85%, respectively, compared to the scaffold containing 0.75 wt% GO. A crack extension model combined with experiment results was proposed to better understand reinforcement mechanisms. Additionally, the scaffold containing GO@CNT exhibited benign cytocompatibility with a cell-spreading area of 86.31% and cell density of 564 cells/mm2 after culturing for 5 d according to the results of cell adhesion and immunofluorescence tests, making it a promising candidate for bone defect repair.

Hollow Cobalt Selenide-Carbon polyhedron sandwiched between reduced graphene oxide nanosheets: A superior anode material for lithium-ion batteries

In this work, a double carbon-confined sandwich-like CoSe/NCP/rGO composite was fabricated using an self-assembled method combined with a selenization treatment. In the composite, cobalt selenide (CoSe) nanoparticles were embedded in N‑doped hollow carbon polyhedrons (NCP) and sandwiched between reduced graphene oxide (rGO) nanosheets. The kinetics of electron/ion transport along with the structural stability of the composite were significantly enhanced by the layer-by-layer sandwiched hollow structure and the strong cohesive interface interaction between various components. The CoSe/NCP/rGO, when serving as LIB’s anode material, exhibited excellent performance. It demonstrated a high specific capacity with the value of 843 mAh/g at 1 A/g, superior high-rate capability with capacity remaining at 309 mAh/g at 10 A/g, long-term cycling stability with no noticeable capability fading over 1000 loops. More importantly, these results were achieved without additional conductive agents.

Femtogram-Sensitive Cantilever Platform for Dynamic Graphene Oxide Nanosheet Monitoring.

This study introduces a new approach to optimizing graphene oxide (GO) properties using liquid-phase plasma treatment in a microenvironment. Our innovation exploits atomic force microscopy (AFM) cantilever frequency tracking to monitor mass variations in GO, which are indicative of surface oxidation-reduction processes or substituent doping (boron/nitrogen). Complementary in situ Raman spectroscopy has observed D/G band shifts, and X-ray photoelectron spectroscopy (XPS) determined the C/O ratio and B/N doping levels pre- and post-treatment, confirming chemical tuning to GO. We can achieve femtogram-level precision in detecting nanomaterial mass changes by correlating elemental ratios with AFM cantilever frequency measurements. This multifaceted approach not only enhances our understanding of the chemical properties of GO but also establishes a new, versatile method for monitoring, modifying, and optimizing the properties of nanomaterials.

NiCoZn Oxide Nanocages on Reduced Graphene Oxide Nanosheets for the Electrochemical Detection of Luteolin

NiCoZn Oxide Nanocages on Reduced Graphene Oxide Nanosheets for the Electrochemical Detection of Luteolin

Emulsion-Based Multiscale Structural Design Realizes Lightweight and Superelastic Graphene Aerogels for Electromagnetic Interference Shielding.

Ultralight graphene aerogels with high electrical conductivity and superelasticity are demanded yet difficult to produce. A versatile emulsion-based approach is demonstrate to optimize multiscale structure of lightweight, elastic, and conductive graphene aerogels. By constructing Pickering emulsion using graphene oxide (GO), poly (amic acid) (PAA), and octadeyl amine (ODA), micron-level close-pore structure is realized while thermal shrinkage mismatch between GO and PAA creates numerous nanowrinkles during thermal annealing. GO nanosheets are bridged by PAA-derived carbon, enhancing the structural integrity at molecular level. These multiscale structural features facilitate rapid electron transport and efficient load transfer, conferring graphene aerogels with intriguing mechanical and electromagnetic interference (EMI) shielding properties. The emulsion-based graphene aerogel with an ultralow density of ≈3.0mg cm-3 integrates outstanding electrical conductivity, air-caliber thermal insulation, high EMI shielding effectiveness of 75.0dB, and 90% strain compressibility with superb fatigue resistance. Intriguingly, thanks to the gel-like rheological behavior of the emulsion, ultralight graphene scaffolds with programmable geometries are obtained by 3D printing. This work provides a general approach for the preparation of ultralight and superelastic graphene aerogels with excellent EMI shielding properties, showing broad application prospects in various fields.

Antimicrobial and antibiofilm effects of cyclic dipeptide-rich fraction from Lactobacillus plantarum loaded on graphene oxide nanosheets.

One effective method to combat bacterial infections is by using bacteria itself as a weapon. Lactobacillus is a type of fermenting bacterium that has probiotic properties and has demonstrated antimicrobial benefits against other bacteria. Cyclodipeptides (CDPs), present in the supernatant of Lactobacillus, possess several antimicrobial properties. In this study, the CDP fraction was isolated from the supernatant of Lactobacillus plantarum (L. plantarum). This fraction was then loaded onto graphene oxide nanosheets (GO NSs). The study assessed the substance's ability to inhibit bacterial growth by using the minimum inhibitory concentration (MIC) method on A. baumannii and S. aureus strains that were obtained from clinical samples. To determine the substance's impact on biofilm formation, the microtiter plate method was used. Moreover, the checkerboard technique was employed to explore the potential synergistic effects of these two substances. According to the study, the minimum inhibitory concentration (MIC) of the desired compound was found to be 1.25 mg/mL against S. aureus and 2.5 mg/mL against A. baumannii. Furthermore, at a concentration of 10 mg/mL, the compound prevented 81.6% (p < 0.01) of biofilm production in A. baumannii, while at a concentration of 1.25 mg/mL, it prevented 47.5% (p < 0.05) of biofilm production in S. aureus. The study also explored the synergistic properties of two compounds using the checkerboard method. In general, we found that GO NSs possess antimicrobial properties and enhance cyclodipeptides' activity against S. aureus and A. baumannii.

Nanoarchitectonics with reduced graphene oxide nanosheets for photo- and humidity sensing properties

The present study explores the photo- and humidity sensing properties of reduced graphene oxide (rGO) sheets at room temperature. Graphite powder was chemically oxidized using a modified Hummer's approach to produce rGO sheets. The physicochemical traits of the rGO sensor were analyzed by various characterization techniques, including X-ray diffraction (XRD), UV–vis absorption spectra, Raman spectroscopy, field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HR-TEM). Raman spectroscopic micrograph exhibits two vibrational modes: D-band at 1329 and G-band at 1587 cm−1. The rGO photosensor shows a maximum responsivity of about 7.22 AW−1 with quick response and recovery times. The sensor showed a maximum sensitivity of 37 % in humid environments, with response and recovery durations of 44 s and 126 s, respectively. The rGO-based sensor showed excellent photosensitivity, exceptional stability, and a better response to photo and humid environments. The excellent performance of rGO sheets proves to be a promising functional material in sensing devices.

Investigation of the gamma ray shielding properties of Epoxy based on Bi2O3/GO nanocomposite

Abstract One of the important carbon materials, graphene oxide (GO), has several oxygen-containing functional groups. Due to its unique structure, it has attracted increasing interest in multidisciplinary studies of physical and chemical attributes. In this work, Bismuth Oxide nanoparticles (Bi2O3) is prepared and functionalized with graphene oxide nanosheets (Bi2O3-GO). The Bi2O3 and Bi2O3-GO nanocomposite were mixed with epoxy by changing the percentages to 1%, 2.5%, 5%, and 10%. The study used a hyper-pure germanium detector to investigate the attenuation characteristics of the prepared samples. Ba133, Cs137, and Co60 point sources were used at photon energies of 81, 276, 302, 356, and 383 keV for Ba133, 661 keV for Cs137, and 1173 and 1332 keV for Co60. The linear attenuation coefficient, mass attenuation coefficient, half-value layer, and tenth-value layer were estimated to investigate the radiation shielding characteristics of the prepared samples. The linear attenuation coefficient (μ) values varied from 0.45 to 0.88, 0.23 to 0.89, and 0.31 to 0.77 for Ba133, Cs137, and Co60, respectively. The mass attenuation coefficient (μm) values varied from 0.18 to 0.50, 0.19 to 0.50, and 0.15 to 0.50 for Ba133, Cs137, and Co60, respectively. Half-value layer (HVL) values varied from 0.79 to 1.55, 0.78 to 3.07, and 0.9 to 2.26 for Ba133, Cs137, and Co60, respectively. Tenth-value layer (TVL) values varied from 2.61 to 5.16, 2.58 to 10.19, and 2.98 to 7.51 for Ba133, Cs137, and Co60, respectively.

An Experimental Evaluation of Compressive Performance of Cement Based Materials with Graphene Oxide Nanosheets (GO) and Ground Granulated Blast Furnace Slag (GGBS)

An Experimental Evaluation of Compressive Performance of Cement Based Materials with Graphene Oxide Nanosheets (GO) and Ground Granulated Blast Furnace Slag (GGBS)

Synthesis and characterization of fluorinated graphene oxide nanosheets derived from Lissachatina fulica snail mucus and their biomedical applications.

The modern nanomedicine incorporates the multimodal treatments into a single formulation, offering innovative cancer therapy options. Nanosheets function as carriers, altering the solubility, biodistribution, and effectiveness of medicinal compounds, resulting in more efficient cancer treatments and reduced side effects. The non-toxic nature of fluorinated graphene oxide (FGO) nanosheets and their potential applications in medication delivery, medical diagnostics, and biomedicine distinguish them from others. Leveraging the unique properties of Lissachatina fulica snail mucus (LfSM), FGO nanosheets were developed to reveal the novel characteristics. Consequently, LfSM was utilized to create non-toxic, environmentally friendly, and long-lasting FGO nanosheets. Ultraviolet-visible (UV-vis) spectroscopy revealed a prominent absorbance peak at 235 nm. The characterization of the synthesized FGO nanosheets involved X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), and atomic force microscopy (AFM) analyses. The antimicrobial activity data demonstrated a broad spectrum of antibacterial effects against Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The cytotoxicity efficacy of LfSM-FGO nanosheets against pancreatic cancer cell line (PANC1) showed promising results at low concentrations. The study suggests that FGO nanosheets made from LfSM could serve as alternate factors for in biomedical applications in the future.

Fabrication of NbTe2@rGO nanosheet by hydrothermal route for cost-effective supercapacitor electrode

The expansion of energy storage devices with extensive stability and high energy density is a crucial area of research that requires immediate attention. In light of these requirements, it was worth noting that supercapacitor (SCs) exhibit great potential as viable options for achieving these demands. Supercapacitor (SCs) despite their potential currently exhibit energy density levels that fall short of the necessary threshold for long-term applications. This limitation primarily stems from the challenge of identifying the ideal materials to enhance their performance. However, transition metal tellurides have a well-studied group of materials that have garnered noticeable consideration because of high energy density. Herein, we present a novel hydrothermal method that involves the fabrication of reduced graphene oxide (rGO) nanosheet combined with niobium telluride (NbTe2) material. However, the NbTe2@rGO nanohybrid's specific capacitance (Csp) was 1475 F g−1, which was approximately twice as high as the specific capacitance of the NbTe2 (667 F g−1) electrode with a specific capacity of 826 C/g at 1 A g−1 which could be ascribed to interconnection between nanoparticles and nanosheets in the NbTe2@rGO nanohybrid with lower Rct = 0.02 Ω and outstanding cycling stability even after undergoing 7000th cycles with a capacitance retention of (97 %). The NbTe2@rGO nanohybrid demonstrated an impressive power density of 285 W kg−1 and energy density of 22 Wh kg−1 at 1 A g−1 in its symmetric two-electrode performance. The findings of this investigation suggested that NbTe2@rGO nanohybrid exhibits promising material for future energy storing devices.

Graphene oxide nanosheets decorated with Gold-Silver core-shell using pulsed laser ablation technique

Graphene oxide nanosheets decorated with Gold-Silver core-shell using pulsed laser ablation technique

Precise control of transmembrane current via regulating bionic lipid membrane composition.

The transport of ions through biological ion channels is regulated not only by their structural characteristics but also by the composition of the phospholipid membrane, which serves as a carrier for nanochannels. Inspired by the modulation of ion currents by lipid membrane composition, exemplified by the activation of the K+ channel of Streptomyces A by anionic lipids, we present a biomimetic nanochannel system based on combining DNA nanotechnology with two-dimensional graphene oxide (GO) nanosheets. By designing multibranched DNA nanowires, we assemble programmable DNA scaffold networks (DSNs) on the GO surface to precisely control membrane composition. Modulating the DSN layers from one to five enhances DNA composition, yielding a maximum 12-fold enhancement in ion current, primarily due to charge effects. Incorporating DNAzymes facilitates reversible modulation of membrane composition, enabling cyclic conversion of ion current. This approach offers a pathway for creating devices with highly efficient, tunable ion transport, applicable in diverse fields like mass transport, environmental protection, biomimetic channels, and biosensors.

Boosting the H2/CO2 and H2/N2 selectivities of a graphene oxide membrane by shrinking the membrane interlayer spacing via thermal treatment

Graphene oxide (GO) membranes have been widely studied and used for gas separation processes, but some structural changes are necessary to guarantee high membrane selectivities. The thermal reduction process stands out for reducing the interlayer channel size of the GO nanosheets to improve the molecular sieving mechanism. Herein, thermally annealed GO layers were deposited on the outer surface of porous alumina hollow fiber substrates and the produced composite membranes were tested for selective hydrogen (H2) separations. The influence of the thermal annealing process at different mild temperatures (80 and 160 °C) on the characteristics of the GO structure was investigated towards the improvement of the membrane efficiency for H2 separation. ATR-FTIR results confirmed the elimination of oxygenated groups, and XRD analyses showed the GO interlayer space decreased from 8.71 to 7.38 Å after the thermal annealing process at 160 °C. The GO thermally annealed membrane presented an H2 permeance of 2032.47 ± 101.69 GPU and an H2/N2 selectivity of 12.16 ± 0.30, which is 315% greater than the selectivity of the pristine GO membrane. Hence, the application of the thermal reduction method to produce GO membranes with greater selectivities is a viable alternative to deal with gas separation processes.

Tailored GO nanosheets for porous framework to high CO2 adsorption

The 2D graphene oxide (GO) is promising for CO2 adsorption, benefitting from its theoretically high specific surface area and abundant oxygen-containing groups. However, the GO nanosheets aggregation renders the loss of CO2 adsorption site, reducing the CO2 adsorption capability. To tackle this issue, we propose of tailoring physical and chemical structures of the GO nanosheet by etching and oxidation, which concurrently enhance the specific surface area and oxygen-containing functional groups. The etching step creates additional in-plane nanopores in the GO nanosheet and uncovers the inaccessible sites on the GO nanosheet. The oxidation step produces more oxygen-containing groups, i.e., active sites, to intensify the CO2 adsorption of GO nanosheets. Resultantly, through enhancing pore volume and interaction between CO2 and oxygenic functional group, the adsorption capacity of CO2 is promoted. As such, the CO2 adsorption capability of GO nanosheets is significantly enhanced. The optimized oxidized porous GO nanosheets are employed for CO2 adsorption after Ca2+ crosslinking, which realizes a high CO2 adsorption capability of 2.5 mmol/g at 298 K, 1 bar. Together with its prominent running stability, the fabricated porous GO-based adsorbents show great potential for CO2 capture to mitigate the current greenhouse gas dilemma.

Iron nanoparticles supported on graphene nanosheets by pulsed laser ablation method in deionized water

In this study, pulsed laser ablation process (PLA) in deionized water solution was used to prepare graphene oxide (GO) nanosheets, wustite (FeO) nanoparticles and GO based FeO nanoparticles. The effect of composition ratio of materials on their optical properties was studied. The structural properties of the materials were characterized using transmission electron microscopy (TEM) and x-ray diffraction (XRD) techniques. According to the TEM results, FeO nanoparticles were well deposited on GO nanosheets. The XRD results demonstrated the formation of Fe and wustite (FeO) phase of iron oxide nanoparticles. In the XRD analysis of graphene sample, graphene oxide (GO) and reduced graphene oxide (rGO) nanosheets were identified. The absorption measurement of the samples in colloidal state was performed using a UV–vis single beam spectrophotometer in the wavelength range of 250 to 800 nm. The higher and the lower absorbance belonged to 1.4 ml GO − 0.6 ml FeO composition and GO nanosheets, respectively. The linear optical properties of the samples, including the real and imaginary parts of the dielectric function, refractive index, extinction coefficient and absorption coefficient were calculated using the spectroscopic ellipsometry (SE) method. Leng oscillator was used as the optical model in SE method. Also, the energy band gap of the samples was calculated using Tauc relation, in which the lower and the higher energy band gaps were obtained for GO nanosheets (3.40 eV) and FeO nanoparticles (4.65 eV), respectively. Furthermore, the nonlinear optical properties of GO based FeO nanoparticles were investigated by Z-scan measurement. The nonlinear refractive index and nonlinear absorption coefficient were obtained in the order of 10−8 cm2 W−1 and 10–4 cm W−1, respectively.

A robust amphiphilic ionic covalent organic framework intercalated into functionalized graphene oxide hybrid membranes for ultrafast extraction uranium from wastewater

The efficient capture of uranium from wastewater is crucial for environmental remediation and the sustainable development of nuclear energy, yet it poses considerable challenges. In this study, amphiphilic ionic covalent organic framework intercalated into graphene oxide (GO) nanosheets functionalized with polyethyleneimine (PEI) were used to construct hybrid membranes with ultrafast uranium adsorption. These hybrid membranes achieved equilibrium in just 10 min and the adsorption capacity was as high as 358.8 mg g−1 at pH = 6. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) analyses revealed that the strong interaction between sulfonic acid groups and uranyl ions was the primary reason for the high adsorption capacity and selectivity. The extended transition state and natural orbitals for chemical valence (ETS–NOCV) analysis revealed that the interaction between the 7 s and 5f orbitals of uranyl and the 2p orbitals of S and O in the sulfonate was the primary reason for the strong interaction between the sulfonate and the uranyl ion. This research presents an effective method for the rapid extraction of uranium from wastewater.

Anti-cancer and visible-light-driven photocatalyst activities of graphene oxide nanosheets against A549 lung cancer cells and organic dyes

The use of graphene oxide (GO) nanosheets (NSs) in cancer cell treatment is a promising and innovative approach to eradicate lung cancer cells and to adsorb and photodegrade organic dyes in water. XRD results revealed that the produced GO NSs have a high crystallinity and a d-spacing value of 0.87 nm. The FTIR spectrum showed that several oxygen-containing functional groups were introduced at the graphite surface from the exfoliation process. The TGA curve result supported the synthesis of GO NSs from the characteristic weight loss behavior. The wrinkled and fold surface morphology of the synthesized GO NSs was confirmed using FE-SEM and TEM. Subsequently, the assessment of their in vitro anti-oxidant and hydroxyl radical scavenging characteristics revealed that the synthesized GO NSs possessed effective antioxidant properties. The viability of A549 lung cancer cells against GO NSs was found to decrease in a dose-dependent manner and their morphology and nuclear damages was assessed by AO/EB and DAPI staining assays. The increased oxidative stress resulted in greater apoptotic cell death, loss of nuclear integrity, and mitochondrial membrane damage against A549 lung cancer cells. The increasing caspase-3 and caspase-9 activation resulted in more apoptotic cell death and cell cycle arrest as determined by flow cytometry. Further, GO NSs demonstrated moderate photocatalytic activity under visible light irradiation, degrading methylene blue (MB) and bromothymol blue (BTB) dye molecules by 44 and 53.5 %, respectively, after 120 min irradiation. Finally, the present study demonstrated that GO NSs possess excellent anti-cancer and moderate photocatalyst activities.

Ultrastrong, Ductile, Tear- and Folding-Resistant Polyimide Film Doubly Reinforced by an Aminated Rigid-Rod Macromolecule and Graphene Oxide.

As a high-performance polymer with exceptional mechanical, thermal, and insulating properties, polyimide (PI) has been widely used as flexible circuit substrates for microelectronics, portable electronics, and wearable devices. Due to the growing demand for further thinning and lightweighting of electronic products, PI films need to have further enhanced mechanical properties. Traditional nanofiller-reinforced PI films often exhibit reduced ductility and limited improvements in strength. Therefore, it remains a challenge to simultaneously improve the strength and toughness of PI films while preserving their ductility. In this study, we report an exceptionally strong and ductile PI doubly reinforced by one-dimensional rigid-rod para-aramid, poly(p-aminophenylene aminoterephthalamide ((NH2)2-PPTA), and two-dimensional graphene oxide (GO) nanosheets. The amino side groups of (NH2)2-PPTA react with the anhydride end groups of PI, forming covalent bonds. At a (NH2)2-PPTA content of only 0.4 wt %, the (NH2)2-PPTA/PI film displays significantly enhanced mechanical properties. When 0.4 wt % of GO is added together with (NH2)2-PPTA, the tensile strength, tensile toughness, and strain at break reach 284.8 ± 5.3 MPa, 277.9 ± 7.6 MJ/m3, and 132.6 ± 3.8%, which are ∼178, ∼312, and ∼51% higher, respectively, than those of pure PI. Moreover, the doubly reinforced PI film also exhibits a 206% increase in tear strength and significantly enhanced folding resistance. The dual reinforcement of PI with (NH2)2-PPTA and GO improves the mechanical properties more efficiently than any single reinforcing agents previously reported and overcomes the disadvantage of most inorganic nanofillers that reduce ductility.

Enhancing fiber-reinforced asphalt binders via graphene oxide grafting: A novel interfacial modulation strategy

This study reports a novel interfacial enhancement strategy for fiber-reinforced asphalt binders. The graphene oxide (GO) nanosheets were used and grafted onto polyester (PET) and polyacrylonitrile (PAN) fibers in order to enhance the performance of modified asphalt binders. Prior to this, ultraviolet ozone (UVO) treatment was primarily adopted for activating the inert surface of fibers. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Scanning electron microscope (SEM) confirmed that GO-modified fibers were successfully prepared via surface modification. For the rheological properties determined by dynamic shear rheometer (DSR), the asphalt binders with GO-modified fibers exhibit improved high-temperature rutting resistance, better creep and recovery characteristics and increased anti-fatigue properties. Remarkably, it demonstrates that the recovery (R) value of GO-PAN modified asphalt binder is increased by 21.9 %, and the non-recoverable compliance (Jnr) value of GO-PET modified asphalt binder has been reduced by 31.9 % compared to that reinforced with the unmodified fiber in multiple stress creep recovery (MSCR) tests. These enhancements are mainly attributed to the increased roughness and modulus of the GO-grafted fibers, which promote effective stress transfer at the fiber-asphalt interfaces. Results from the atomic force microscope (AFM) indicate that the Young’s modulus of GO-PET and GO-PAN is 94.2 % and 260.0 % higher than that of PET and PAN, respectively. This research not only provides a simple and cost-effective method for improving the rheological performance, but also elucidates the enhancement mechanism of interfacial behavior in fiber-reinforced asphalt binders.