Graphene Oxide Nanocomposite Materials Research Articles

Recent Progress in Marine Antifouling Technology Based on Graphene and Graphene Oxide Nanocomposite Materials

Sea vessels and artificial sea‐based structures are severely affected by biofouling, i.e., the formation of deposits of living and dead marine organisms that belong to different species and range in size from unicellular bacteria to multicellular seaweed and mussels. This is a significant engineering problem since they essentially alter the geometry of the hull, increasing friction and reducing the speed of vessels, thus increasing the cost and environmental footprint of transportation. Given the scale of global transportation reaches several billion tons per year, the socioeconomic consequences of the reduction in transit speed and increased consumption of fuel continue to drive researchers and engineers to develop strategies to combat the processes of marine biofouling. Many types of antifouling paints, coatings, and materials that have been designed and tested, and in some instances used commercially, suffer from shortcomings ranging from environmental toxicity to limited efficiency and durability. In this review article, a brief overview of the traditional antifouling materials is presented and recent achievements in the design of advanced antifouling materials based on such nanomaterials as graphene, nanotubes, nanoparticles, and more complex nanostructures are discussed. These materials exhibit excellent antifouling properties and candrive a breakthrough in how marine biofouling is tackled.

Synthesis and characterization of bio-nanocomposites: Functionalization of graphene oxide with a biocompatible amino acid

Graphene oxide (GO) is a complicated composite which can be synthesized from graphite or other carbon sources by a simple top-down method. Graphene is a two-dimensional carbon sheets which can be oxidized to synthesis its oxide structure. The graphene oxide sheets can be functionalized in order to be used actively in different areas. The graphene oxide nanocomposite materials have attracted researches and scientists’ attention due to their wade applications from electrochemical industry to drug delivery. In this novel work the authors have synthesized graphene oxide films and then functionalized with an amino acid, Lysine, and Cu in order to synthesize the Lysine-Cu-Graphene oxide combination. The novelty of this investigation is the authors have functionalized graphene oxide with l-lysine as an amino acid at diverse temperature. Also, this product is environmentally friendly product since it is soluble in aqueous medium and can be applied as an active antibacterial material. After the synthesizing process, the obtained materials had been characterized using different techniques such as Fourier-transform infrared spectroscopy (FTIR) to confirm the success of the functional reaction. Ultra violet visible (UV–Vis) spectroscopy, atomic force microscopy (AFM), X-ray diffraction (XRD), and thermal gravimetric (TG) analysis, were also utilized to approve the covalent attachment of Lysine and also to show the improvement in the thermal stability of GO.

Silver/reduced graphene oxide nanocomposite materials synthesized via a green molecular level mixing

The fabrication of nano reinforced metal matrix composites (MMCs) is scientifically essential to further upgrade the thermal, electrical, and mechanical properties of current MMCs. Here, we present a green molecular mixing (MLM) of silver (Ag) and graphene (G) to overcome these challenges. Experimental results show that the green MLM allows to homogeneously mix 3 vol. % of G as observed with traditional MLM while adding a control on the oxidation steps. Metal and GO reductions can be precisely control by varying the solution temperature. Highly thermal conductivity and strong elastic modulus nanocomposites are fabricated making it an eco-friendlier mixing process.

Novel functionalized magnetic graphene oxide nanocomposite material for efficient vanadium(V) capturing from tea samples

Novel functionalized magnetic graphene oxide nanocomposite material for efficient vanadium(V) capturing from tea samples

Synthesis of titanium dioxide/reduced graphene oxide nanocomposite material via the incorporated hydrothermal co-precipitation method for fabricating photoanode in dye-sensitized solar cell

This study first investigates the preparation and characterization of titanium dioxide/reduced graphene oxide (TiO2/rGO) and then proposes the fabrication of photoanode in dye-sensitized solar cell (DSSC) from synthesized materials. Herein, the TiO2/rGO nanocomposites were prepared by the incorporation of hydrothermal approach and co-precipitation method from the precursors of titanium (IV) isopropoxide and graphene oxide. The fabrication of photoanode from the as-prepared TiO2/rGO nanocomposite paste was carried out using screen-printing technique. The performance of fabricated DSSCs was evaluated by current density-voltage curves and electrochemical impedance spectroscopy. The characterizations of TiO2 nanoparticles, TiO2/rGO nanocomposites, and their precursors were confirmed by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and transmission electron microscopy. Experimental data showed that the optimal rGO weight percentage of 0.6% in the TiO2/rGO nanocomposite material fabricated DSSC successfully with the highest values of short-circuit current density (17.65 mA/cm2) and energy conversion efficiency (7.46%), approximately increasing 24% and 25%, respectively, in comparison with the pristine TiO2 material. Characterization results indicated that the incorporated hydrothermal co-precipitation method was efficient in producing well-defined spherical TiO2 nanoparticles decorated on the rGO sheets with an average diameter of 20–25 nm. Therefore, the TiO2/rGO nanocomposites with the eco-friendly and efficient synthesis method are highly promising for manufacturing and commercializing DSSCs widely.

Self-combustion synthesized NiFe2O4/reduced graphene oxide composite nanomaterials: Effect of chelating agent type on the crystal structure and magnetic properties

Ultrafine nickel ferrite and nickel ferrite/reduced graphene oxide nanocomposite materials have been synthesized by self-combustion method using glycine, citric acid and urea as chelating agent. The comparative analysis of structural and magnetic properties of the obtained materials in a temperature range of 300–900 °C has been performed. The changes in average particle sizes of spinel phase for NiFe2O4 and NiFe2O4/reduced graphene oxide materials have been analyzed from the point of view of the metal-organic complexes interaction and different mechanisms of gel formation for glycine, citric acid and urea based materials. The conditions of ferrimagnetic and superparamagnetic states formation of nickel ferrite nanoparticles have been investigated by Mossbauer spectroscopy.

Removal of the antibiotic sulfamethoxazole from environmental water by mesoporous silica-magnetic graphene oxide nanocomposite technology: Adsorption characteristics, coadsorption and uptake mechanism

In this study, the mesoporous silica-magnetic graphene oxide nanocomposite material (mGO-Si) was prepared. The surfactant cetyltrimethyl ammonium bromide (CTAB) was utilized as the mesoporous template while the tetraethyl orthosilicate (TEOS) was used as the silica source. The synthesized nanocomposite was characterized through different analyses, namely XRD, XPS, TEM, FT-IR, VSM, BET, and acid-base titration. Various factors like the effects of the initial concentration, contact time, influence of the pH and the coexistence of other antibiotics on the sulfamethoxazole (SMX) uptake, were investigated. Adsorption results exhibited that the mGO-Si adsorbed the SMX molecules more effectively than the pristine magnetic graphene oxide (mGO). Kinetic data showed good correlation on the basis of the pseudo-second-order model. The equilibrium adsorption data fitted well to the Langmuir model, and a maximum SMX adsorption capacity of 15.46 mg/g was obtained. At high pH, the solution had significantly impaired then declined capacity of SMX adsorption. Electrostatic repulsion occurred between the dissociated SMX and the more negatively charged mGO-Si at basic pH. Adsorption mechanisms between SMX and mGO-Si were plausibly activated by hydrogen bonding, π–π EDA interactions, and solution pH-based electrostatic interactions dependent upon the status of SMX and the pH,PZC of mGO-Si. Moreover, the CIP and OTC competitors in the mixed solute system managed to improve the SMX adsorption by acting as a bridge to form CIP−SMX−mGO-Si/ OTC−SMX−mGO-Si surface complex. At low aqueous phase concentration of SMX, CIP was likely to form a stronger electrostatic interaction system with the adsorbent, thereby resulting in an adsorption level which was more competitive in the process opposing CIP to SMX than in that opposing OTC to SMX.

Synthesis and Characterization of ZnO-decorated GO Nanocomposite Material with Different ZnO Loading through Sol-gel Method

This work aimed is to synthesis a well dispersed zinc oxide (ZnO) nanoparticles (NPs) decorated on graphene oxide (GO) nanosheet with a practical way by using sol-gel technique. Zinc acetate dehydrate (Zn(CH3COO) 2·2H2O) was used as precursor of ZnO and absolute ethanol as solvent. 1 weight percent (wt%), 5 wt%, 10 wt%, and 20 wt% of ZnO was decorated on GO nanosheet. A series of analysis was carried out to characterize the synthesized ZnO-decorated GO nanocomposite material. The results of XRD analysis show some long area of peak at 25° to 80° allocate for ZnO in the ZnO-decorated GO nanocomposite material. By performing zeta potential analysis, the findings show that there was increment of negative surface charge on ZnO-decorated GO nanocomposite material. The experiment result also found that the hydrodynamic particle size of ZnO-decorated GO nanocomposite material become larger when high ZnO loaded. FESEM micrographs demonstrated that spherical-shaped of ZnO NPs appeared on the GO nanosheet with further proved by EDX where the content of ZnO-decorated GO nanocomposite material was composed by 71.3 wt% of C, 17 wt% of O, and additional element of 11.7 wt% of Zn. Thus, it can summarize that the synthesized ZnO-decorated GO nanocomposite material was high in purity. The findings in this study proved that ZnO NPs loading in ZnO-decorated GO nanocomposite material were successfully synthesized by sol-gel method. A ZnO-decorated GO nanocomposite material with layering ZnO NPs on GO nanosheet was produced.

Bioinspired gold nanoparticles decorated reduced graphene oxide nanocomposite using Syzygium cumini seed extract: Evaluation of its biological applications

The development of novel functionalized reduced graphene oxide nanocomposite materials keeping in mind environmental and health perspectives via green approaches is currently gaining enormous research interest in the field of nanoscience and nanotechnology. Herein, we report a bio-inspired green synthesis approach for gold nanoparticles decorated reduced graphene oxide nanocomposite in which Syzygium cumini seed extract (SCSE) is applied as natural reducing and stabilizing agent for the simultaneous reduction of chloroauric acid and graphene oxide (GO). The obtained nanocomposite was thoroughly investigated using UV–visible and FT-IR spectroscopy, XRD, SEM-EDX, TEM-SAED, Raman spectroscopy and XPS analysis. These characterization techniques clearly confirmed the successful synthesis of gold nanoparticles decorated reduced graphene oxide nanocomposite. In addition, this study evaluated the systematic and detailed analysis of AuNPs-rGO-NC and its efficacy towards cellular and antibacterial toxicological behavior. A detailed in-vitro cytotoxicity study was performed by analysing the percentage inhibition of cell viability, generation of reactive oxygen species (ROS) in cell lines using 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide (MTT) assay on human colorectal (HCT116) and lung (A549) cancer cell lines. Further, antibacterial toxicological evaluation was performed by analysing diameter of inhibition Zone (DIZ), activity index (AI), minimum bactericidal concentration (MBC), minimum inhibitory concentration (MIC), growth kinetics (GrK) and death kinetics (DeK) against Gram-negative bacterial strain Escherichia coli and Gram-positive bacterial strains Staphylococcus aureus and Bacillus subtilis. The cytotoxicity and antibacterial toxicological assays revealed that the synthesized nanocomposite showed significant anti-cancer activity towards A549 cell line and Gram-negative bacterial strain Escherichia coli compared to the rest.

Ultrathin Graphene-Protein Supercapacitors for Miniaturized Bioelectronics.

Nearly all implantable bioelectronics are powered by bulky batteries which limit device miniaturization and lifespan. Moreover, batteries contain toxic materials and electrolytes that can be dangerous if leakage occurs. Herein, an approach to fabricate implantable protein-based bioelectrochemical capacitors (bECs) employing new nanocomposite heterostructures in which 2D reduced graphene oxide sheets are interlayered with chemically modified mammalian proteins, while utilizing biological fluids as electrolytes is described. This protein-modified reduced graphene oxide nanocomposite material shows no toxicity to mouse embryo fibroblasts and COS-7 cell cultures at a high concentration of 1600 μg mL-1 which is 160 times higher than those used in bECs, unlike the unmodified graphene oxide which caused toxic cell damage even at low doses of 10 μg mL-1. The bEC devices are 1 μm thick, fully flexible, and have high energy density comparable to that of lithium thin film batteries. COS-7 cell culture is not affected by long-term exposure to encapsulated bECs over 4 d of continuous charge/discharge cycles. These bECs are unique, protein-based devices, use serum as electrolyte, and have the potential to power a new generation of long-life, miniaturized implantable devices.

Bismuth oxyiodide incorporated reduced graphene oxide nanocomposite material as an efficient photocatalyst for visible light assisted degradation of organic pollutants

Herein, Bismuth oxyiodide (BiOI) – reduced graphene oxide (rGO) photocatalysts were prepared via simple hydrothermal method. The BiOI-rGO photocatalyst exhibited high crystallinity with tetragonal phase of BiOI. In addition, the electronic interaction between rGO sheet and BiOI reduced the band-gap value from 1.86eV of bare BiOI to 1.51eV of BiOI-rGO (6wt%) photocatalyst. More interestingly, the rGO showed a strong influence on tailoring the morphology of BiOI to different nanostructures with different rGO loading (wt%), which further reflected differences in the photocatalytic activity. A significant quenching in the photoluminescence intensity of rGO supported BiOI photocatalyst confirmed the effective suppression of electron-hole pair recombination. The optimized rGO (4wt%) loaded BiOI photocatalyst significantly improved the photocatalytic activity (∼85%) towards the degradation of methyl orange (MO) dye compared to that of pristine BiOI (∼29%). Thus, around three folds enhancement in the photocatalytic activity of BiOI–rGO (4wt%) catalyst was mainly attributed to ultrafast separation of electron–hole pairs and rapid transportation of carriers by rGO support. The superior photocatalytic activity demonstrated by this newly synthesized BiOI-rGO photocatalyst makes it’s a potential candidate for environmental remediation process.

Adsorptive interaction of bisphenol A with mesoporous titanosilicate/reduced graphene oxide nanocomposite materials: FT-IR and Raman analyses.

Nanocomposite materials containing graphene oxide have attracted tremendous interest as catalysts and adsorbents for water purification. In this study, mesoporous titanosilicate/reduced graphene oxide composite materials with different Ti contents were employed as adsorbents for removing bisphenol A (BPA) from water systems. The adsorptive interaction between BPA and adsorption sites on the composite materials was investigated by Fourier transform infrared (FT-IR) and Raman spectroscopy. Adsorption capacities of BPA at equilibrium, q e (mg/g), decreased with increasing Ti contents, proportional to the surface area of the composite materials. FT-IR observations for fresh and spent adsorbents indicated that BPA adsorbed onto the composite materials by the electrostatic interaction between OH functional groups contained in BPA and on the adsorbents. The electrostatic adsorption sites on the adsorbents were categorized into three hydroxyl groups: Si-OH, Ti-OH, and graphene-OH. In Raman spectra, the intensity ratios of D to G band were decreased after the adsorption of BPA, implying adsorptive interaction of benzene rings of BPA with the sp2 hybrid structure of the reduced graphene oxide.