Graphene Oxide Content Research Articles

Enriched Graphene Oxide-Polypropylene Suture Threads Buttons Modulate the Inflammatory Pathway Induced by Escherichia coli Lipopolysaccharide.

Graphene oxide (GO), derived from graphene, has remarkable chemical-physical properties such as stability, strength, and thermal or electric conductivity and additionally shows antibacterial and anti-inflammatory properties. The present study aimed to evaluate the anti-inflammatory effects of polypropylene suture threads buttons (PPSTBs), enriched with two different concentrations of GO, in the modulation of the inflammatory pathway TLR4/MyD 88/NFκB p65/NLRP3 induced by the Escherichia coli (E. coli) lipopolysaccharide (LPS-E). The gene and the protein expression of inflammatory markers were evaluated in an in vitro model of primary human gingival fibroblasts (hGFs) by real-time PCR, western blotting, and immunofluorescence analysis. Both GO concentrations used in the polypropylene suture threads buttons-GO constructs (PPSTBs-GO) decreased the expression of inflammatory markers in hGFs treated with LPS-E. The hGFs morphology and adhesion on the PPSTBs-GO constructs were also visualized by inverted light microscopy, scanning electron microscopy (SEM), and real-time PCR. Together, these results suggest that enriched PPSTBs-GO modulates the inflammatory process through TLR4/MyD 88/NFκB p65/NLRP3 pathway.

Microstructure and properties of graphene oxide reinforced copper-matrix composite foils fabricated by ultrasonic assisted electrodeposition

In this paper, graphene oxide (GO)/Cu composite (GO/Cu) foils with high thermal and mechanical properties were prepared by ultrasonic-assisted direct current electrodeposition. The effect of ultrasonic power and graphene concentration on the microstructure and properties of the composite foils was systematically investigated. It was found that the average grain size can be refined by both the addition of GO reinforcement and ultrasonic treatment. Under the optimized preparation condition with 120 W ultrasonic power and GO concentration of 0.8 g/L GO in plating solution, the average grain size was about 0.26 μm and illustrated strong crystallographic orientation of (220). In addition, the GO content in the composites was increased from 0.67 wt% without ultrasonic treatment to 1.72 wt%, and it was uniformly dispersed in the composite foil with ultrasonic effect. Compared with pure copper foil, the hardness value of the GO/Cu composite foil nearly doubled to 74.6 HV0.1, the average friction coefficient was decreased from 0.87 to 0.72 and the tensile strength of the composite foil was improved to 239 MPa with an elongation of 17%. Meanwhile, the thermal conductivity with optimized condition increased 39.8% to 556.57 W m−1 K−1. The improved mechanical and thermal properties of the GO/Cu composite foil were mainly ascribed to the grain refinement, change of preferred orientation and the presence of reduced GO reinforcement as a network in the composite foil.

Graphene oxide exposure alters gut microbial community composition and metabolism in an in vitro human model

Graphene oxide (GO) nanomaterials have unique physicochemical properties that make them highly promising for biomedical, environmental, and agricultural applications.There is growing interest in the use of GO and extensive in vitro and in vivo studies have been conducted to assess its nanotoxicity. Although it is known that GO can alter the composition of the gut microbiota in mice and zebrafish, studies on the potential impacts of GO on the human gut microbiome are largely lacking. This study addresses an important knowledge gap by investigating the impact of GO exposure- at low (25 mg/L) and high (250 mg/L) doses under both fed (nutrient rich) and fasted (nutrient deplete) conditions- on the gut microbial communitys' structure and function, using an in vitro model. This model includes simulated oral, gastric, small intestinal phase digestion of GO followed by incubation in a colon bioreactor. 16S rRNA amplicon sequencing revealed that GO exposure resulted in a restructuring of community composition. 25 mg/L GO induced a marked decrease in the Bacteroidota phylum and increased the ratio of Firmicutes to Bacteroidota (F/B). Untargeted metabolomics on the supernatants indicated that 25 mg/L GO impaired microbial utilization and metabolism of substrates (amino acids, carbohydrate metabolites) and reduced production of beneficial microbial metabolites such as 5-hydroxyindole-3-acetic acid and GABA. Exposure to 250 mg/L GO resulted in community composition and metabolome profiles that were very similar to the controls that lacked both GO and digestive enzymes. Differential abundance analyses revealed that 3 genera from the phylum Bacteroidota (Bacteroides, Dysgonomonas, and Parabacteroides) were more abundant after 250 mg/L GO exposure, irrespective of feed state. Integrative correlation network analysis indicated that the phylum Bacteroidota showed strong positive correlations to multiple microbial metabolites including GABA and 3-indoleacetic acid, are much larger number of correlations compared to other phyla. These results show that GO exposure has a significant impact on gut microbial community composition and metabolism at both low and high GO concentrations.

A crosslinked coral-like Co@CoO/RGO nanohybrid structure with good electromagnetic wave absorption performance

The combination of magnetic and dielectric materials followed by appropriate structure design is an effective approach to achieve high electromagnetic wave absorption properties. Here, crosslinked Co@CoO/reduced graphene oxide nanohybrids (CCRGO) were fabricated via a simple three-step method. The experimental results show that compared with previous works, the as-prepared CCRGO nanohybrids achieve higher electromagnetic wave absorption and broader effective bandwidth at a lower filler loading. The electromagnetic parameters and electromagnetic wave absorption performance could be apparently adjusted by controlling the adding content of graphene oxide (GO) and the reduction temperature. Among a series of samples, CCRGO3-650 nanohybrid yields the best electromagnetic wave absorption performance benefiting from the proper GO addition and reduction temperature. At a filler loading of 20 wt%, the maximal reflection loss reaches to −64.67 dB at a thickness of 2.53 mm and the effective bandwidth below −10 dB covers the whole X band at a thickness of 2.51 mm. The good performance may be ascribed to the advantages of the dielectric and magnetic component as well as the special crosslinked structure, which triggers a synergistic absorption mechanism including multiple reflection/scattering, interface polarization, dipole polarization, conductive loss, eddy current loss, exchange resonance in the electromagnetic wave dissipation process. The good electromagnetic wave absorption performance affirms the potential application of CCRGO nanohybrids in the field of stealth materials.

Effect of Graphene Oxide on the Mechanical Properties and Durability of High-Strength Lightweight Concrete Containing Shale Ceramsite.

An effective pathway to achieve the sustainable development of resources and environmental protection is to utilize shale ceramsite (SC), which is processed from shale spoil to produce high-strength lightweight concrete (HSLWC). Furthermore, the urgent demand for better performance of HSLWC has stimulated active research on graphene oxide (GO) in strengthening mechanical properties and durability. This study was an effort to investigate the effect of different contents of GO on HSLWC manufactured from SC. For this purpose, six mixtures containing GO in the range of 0-0.08% (by weight of cement) were systematically designed to test the mechanical properties (compressive strength, flexural strength, and splitting tensile strength), durability (chloride penetration resistance, freezing-thawing resistance, and sulfate attack resistance), and microstructure. The experimental results showed that the optimum amount of 0.05% GO can maximize the compressive strength, flexural strength, and splitting tensile strength by 20.1%, 34.3%, and 24.2%, respectively, and exhibited excellent chloride penetration resistance, freezing-thawing resistance, and sulfate attack resistance. Note that when the addition of GO was relatively high, the performance improvement in HSLWC as attenuated instead. Therefore, based on the comprehensive analysis of microstructure, the optimal addition level of GO to achieve the best mechanical properties and durability of HSLWC is considered to be 0.05%. These findings can provide a new method for the use of SC in engineering.

Tuning the micro‐structure, laser ignition, and isovolumetric burning performance of nitrocellulose propellant via incorporation of graphene oxide

AbstractNanoscale recombination between carbon nanomaterials (CNs) and polymers has been proposed for a variety of industrial and scientific applications. Composite energetic materials consisting of CNs with novel laser ignition property and tunable combustion performance have attracted people's attention. Here, reported is the novel manufacturing process of uniform nitrocellulose (NC)/graphene oxide (GO) nanocomposite propellant and the micro‐structure, laser ignition and isovolumetric burning features of the propellants introduced by GO. The results of microstructure tests indicated that GO (0.25–2 wt%) was stripped and dispersed homogeneously and dense nanocomposite propellants were prepared successfully through water ultrasonic dispersion, twin‐screw mixture, as well as compression molding. The crystallization of NC was forbidden by doping GO, meanwhile, the thermal stability and thermal conductivity of the composite propellants increased slightly with the addition of GO. The results of laser ignition combustion experiments showed that GO was an efficient additive to shorten the ignition delay time from more than 2000–14 ms when 2 wt% of GO was doped, however, the combustion flame intensity was also weakened due to the addition of GO. The combustion tests in a closed bomb vessel were conducted, and the results showed that GO would not affect the stable combustion of NC at high combustion pressure, moreover, the burning rate and dynamic vivacity of the composite propellants decreased with the increase of GO content.

Fatigue properties and microstructure of graphene oxide/microcapsule self-healing concrete

To meet the unique requirements of durability and conductivity of concrete materials for transformation projects in Northwest China, microcapsules with repair properties were synthesized using a physical method. Graphene oxide was used to prepare standard concrete composite parts as a conductive medium. The orthogonal test determined the optimal dosage of graphene oxide and microcapsules. The fatigue test and microstructure of concrete under static loading and combined dynamic and static loading were investigated, and the effects of graphene oxide and microcapsules on the fatigue resistance of concrete were compared and analyzed. Finally, the microscopic morphology of concrete was analyzed using scanning electron microscopy (SEM) to afford the microscopic mechanism of action for improving the mechanical properties and fatigue damage of concrete. The results show that the optimal mixing ratio of the concrete after 28 days is 3% microcapsule content, 0.1% graphene oxide content, and 0.5 water–cement ratios. Graphene oxide can promote the hydration process of cement and improve the pore structure of the cement matrix to compensate for the loss of strength of concrete internal structure caused by microcapsules. The strong growth rate is not <20%. The fatigue life loss of the group doped with 0.1% graphene oxide alone and the best ratio group was relatively small under different stress levels. The microcapsules were uniformly embedded within the cement matrix, and graphene oxide promoted the formation of a dense microstructure within the material. The synergistic effect of the two ensures structural integrity and denseness.

Exploiting graphene oxide as a potential additive to improve the performance of cold‐mixed epoxy asphalt binder

AbstractAs a green material for high‐performance paving, cold‐mixed epoxy asphalt (CEA) should be improved in compatibility, mechanical performance, and thermal stability. This work is going to estimate the potential of graphene oxide (GO) as an additive for preparing GO/CEA composites with different GO content from 0 to 0.2 wt%. The influences of GO on the structure and performances of CEA were evaluated by Fourier transform‐infrared spectrum, fluorescence microscopy, viscosity, thermogravimetric analysis, tensile test, and dynamic mechanical analysis. Results showed that the functional groups on GO reacted with CEA and improved the compatibility of epoxy resin and asphalt. The viscosity of the GO/CEA composites increased slightly and the pot life decreased significantly, with GO loading increasing. The cured GO/CEA composite with 0.1 wt% GO had the best heat resistance and showed a gentle thermal decomposition. GO improved the toughness of the cured CEA and had a certain weakening effect on its strength. The introduction of GO lowered the glass transition temperature of the cured CEA from 51.4 to 47.1 °C and decreased its storage modulus. The preliminary exploration of this study shows that the modification of GO for CEA is feasible, and it is expected to prolong the service life of CEA.

Artificial Neural Network Model for Membrane Desalination: A Predictive and Optimization Study

Desalination is a sustainable method to solve global water scarcity. A Response Surface Methodology (RSM) approach is widely applied to optimize the desalination performance, but further investigations with additional inputs are restricted. An Artificial neuron network (ANN) method is proposed to reconstruct the parameters and demonstrate multivariate analysis. Graphene oxide (GO) content, Polyhedral Oligomeric Silsesquioxane (POSS) content, operating pressure, and salinity were combined as input parameters for a four-dimensional regression analysis to predict the three responses: contact angle, salt rejection, and permeation flux. Average coefficient of determination (R2) values ranged between 0.918 and 0.959. A mathematical equation was derived to find global max and min values. Three objective functions and three-dimensional diagrams were applied to optimize effective cost conditions. It served as the database for the membranologists to decide the amount of GO to be used to fabricate membranes by considering the effects of operating conditions such as salinity and pressure to achieve the desired salt rejection, permeation flux, contact angle, and cost. The finding suggested that a membrane with 0.0063 wt% of GO, operated at 14.2 atm for a 5501 ppm salt solution, is the preferred optimal condition to achieve high salt rejection and permeation flux simultaneously.

Surface-based modified 3D-printed BG/GO scaffolds promote bone defect repair through bone immunomodulation

Successful bone defect repair requires a favorable immunomodulation. Macrophages are among the frontline cells activated after biomaterial implantation, and biomaterials play a role in the final determination of their fate. The surface properties of biomaterials such as roughness and hydrophilicity can activate macrophages to have an anti-inflammatory phenotype for improving tissue regeneration. Because of its known characteristics, graphene oxide (GO) is widely used in the biomaterials field. GO directly promotes stem cell proliferation and osteogenic differentiation, properties that have been extensively investigated. The aim of this study is to research the effects of the surface-based modified three-dimensional (3D) porous bioactive glass (BG)/GO scaffolds on macrophage activation and bone regeneration. In vivo, compared with the control group receiving BG with a relatively smooth surface, the group receiving the porous implant showed a decreased proinflammatory response in the skin around the implant with increasing GO density, and the 3D porous implant was covered with new bone tissue. In vitro, both Raw264.7 cells and rat bone marrow mesenchymal stem cells (rBMSCs) can adhere and stretch well on rough, hydrophilic BG/GO scaffolds. When Raw264.7 cells were cultured on scaffolds, GO significantly promoted the polarization of M0 macrophages to the M2 type to a certain extent and further promoted the secretion of osteogenic and angiogenic factors, enhancing the osteogenic differentiation of rBMSCs and the angiogenesis of endothelial cells. Further experiments showed that the rough hydrophilic surface of BG/GO might lead to the upregulation of the surface-dependent WNT-3A protein induced by the enhancement of integrin signalling and the accumulation and activation of β-catenin protein in cells. However, excessive content of GO has the opposite regulatory result. These results demonstrate that BG/GO biomaterials with surface-based modification play an important role in bone repair by adjusting the response of macrophages to biomaterials through their surface properties.

The combination of graphene oxide and preservatives can further improve the preservation of cut flowers.

It is reported that the use of nanomaterials can extend the vase life of fresh-cut flowers. Graphene oxide (GO) is one of these nanomaterials that aid in promoting water absorption and antioxidation during the preservation of fresh-cut flowers. In this investigation, the three mainstream brands of preservatives commercially available on the market ("Chrysal," "Floralife," and "Long Life") in combination with low concentrations of GO (0.15 mg/L) were used to preserve fresh-cut roses. The results showed that the three brands of preservatives had different degrees of freshness retention. Compared to the preservatives used alone, the combination of low concentrations of GO with the preservatives, especially in the L+GO group (with 0.15 mg/L GO added in the preservative solution of "Long life"), further improved the preservation of cut flowers. L+GO group showed less level of antioxidant enzyme activities, lower ROS accumulation and cell death rate, and higher relative fresh weight than the other groups, implying a better antioxidant and water balance abilities. GO attached to the xylem duct of flower stem, and reduced the blockage of xylem vessels by bacteria, which were determined by SEM (scanning electron microscopy) and FTIR (Fourier transform infrared) analysis. XPS (X-ray photoenergy spectra) analysis results proved that GO could enter the interior of flower stem through xylem duct, and when combined with "Long Life," the anti-oxidation protection ability of GO was enhanced, thus delaying ageing, and greatly extending the vase life of fresh-cut flowers. The study provides new insights into cut flower preservation using GO.

Recoverable cellulose composite adsorbents for anionic/cationic dyes removal

GO/HEC/PGDE/Fe3O4 materials were successfully fabricated using environmentally-friendly hydroxyethyl cellulose (HEC), poly(ethylene glycol) diglycidyl ether (PGDE), graphene oxide (GO) and magnetic Fe3O4. Systematic investigations were completed to explore the influences of GO content in GO/HEC/PGDE/Fe3O4 and adsorption conditions on the adsorptions of cationic dyes (methylene blue (MB), crystal violet (CV)) and anionic dye acid blue 25 (AB-25). The increase of GO content can remarkably improve the adsorption capacity of GO/HEC/PGDE/Fe3O4 for the dyes. The three kinetic, four isothermic and three thermodynamic models were investigated to reveal the adsorption behaviors of the dyes. The formation of HEC/PGDE/Fe3O4 and adsorption mechanisms of the dyes by GO/HEC/PGDE/Fe3O4 were suggested. The GO/HEC/PGDE/Fe3O4 endowed with easy-fabrication, eco-friendly feature, efficient adsorption capacity of anionic/cationic dyes, convenient separation and reusability has potential applications in wastewater purification industry.

A novel UiO-66-NH2/graphene oxide composite thin membrane for retarding membrane wetting in membrane distillation

Membrane distillation (MD) is considered an emerging desalination technology. However, the presence of surfactants allows liquid to penetrate the membrane, resulting in membrane wetting, which hinders the commercialization of MD. In this study, we use very few modified materials to prepare novel Janus thin membranes that immobilize modified materials (graphene oxide (GO) and UiO-66-NH2) on polytetrafluoroethylene (PTFE) hydrophobic base membranes via crosslinkers. The composite thin membrane properties with eight different ratios and contents of GO and UiO-66-NH2 were fabricated and tested by a feed solution of sodium chloride containing a high concentration of sodium dodecyl sulfate. An optimal ratio of Janus membrane with high flux without affecting the effluent water quality was obtained. The Janus membrane exhibited excellent anti-wetting properties compared to the original PTFE membrane. A desalination rate of up to 99.9% was still available even under 48 h of long-term operating conditions by maintaining a flux of approximately 21.2 L/(m2·h). The anti-wetting mechanism of this membrane was further confirmed by the modified XDLVO model. It suggested that the novel Janus membrane could be a highly promising substitute to the MD process for the resource-based treatment of surfactant-containing wastewater, which played an important role in promoting its application.

Carbon foam composites containing carbon nanotubes and graphene oxide as additives for enhanced mechanical, thermal, electrical and catalytic properties

Based on the versatile nature and applications of Carbon foam (CF), up to now many attempts were performed to improve the structure and properties of CF by incorporating various additives in the CF matrix. But these additives improved one property on the cost of another ones. Herein, we have synergistically incorporated multi-walled carbon nanotubes (MWCNTs) and graphene oxide (GO) with varying loadings as additives in the CF matrix via direct pyrolysis to achieve all the desired properties. Seven different types of CF composites including pure CF were prepared and their effect on the structure, mechanical, thermal, electrical and catalytic characteristics has been reported. The results revealed that after the inclusion of MWCNTs and GO contents, the microstructural performance of CF samples was amazingly improved. Additionally, it was observed that mechanical, thermal, electrical and catalytic behaviors of the CF samples were significantly enhances by the increase of nanohybrids. The compressive strength and Young's modulus reveals their optimum limits up to 19.3 and 57.4 MPa respectively on 2 wt.% MWCNTs-GO additive loadings. Similarly, the greatest thermal and electrical conductivities of 30.92 W/m. K and 27.4 × 103 S/m were showed by CF samples having 2 wt. % MWCNTs-GO loadings. Whereas, the decolorization activity of the CF and their nanocomposites were tested against methyl orange dye and it was observed that the sample with enhanced MWCNTs and GO have good decolorization activity and much sustainable than other samples. The 4% CF/MWCNTs-GO decolorized about 76% MO dye under exposure to UV light within 60 min. The decolorization of MO dye increases with increasing nanocomposite dosage and decreasing initial dye concentration.

Electronic correlations enhance optical absorption in graphene oxide-modified methylammonium lead iodide perovskite

We reveal unusual optical changes accompanied by spectral weight transfer analysis in methylammonium lead iodide (MAPbI3) as a function small fraction of graphene oxide (GO) concentrations using spectroscopic ellipsometry. Interestingly, we observe the tuneable optical properties of MAPbI3 due to the electronic correlation effect induced by GO using spectral weight transfer analysis. The increase of absorption in the MAPbI3 layer indicates a decrease in the number of holes due to the migration of these holes to the GO layer, suggesting the hole transport properties of GO. This work is the first to study the optical properties of GO combined with MAPbI3, which provides critical information that will be of great interest in the future development of high-performance PSCs, as well as how they reconcile several experimental studies that have demonstrated the positive impact of GO on charge extraction.

Graphene oxide addition to anaerobic digestion of waste activated sludge: Impact on methane production and removal of emerging contaminants

The effect of graphene oxide on the anaerobic digestion of waste activated sludge was investigated at two graphene oxide concentrations (0.025 and 0.075 g graphene oxide per g volatile solids) using biochemical methane potential tests. The occurrence of 36 pharmaceuticals was monitored in the solid and liquid phases before and after the anaerobic treatment. The addition of graphene oxide improved the removal of most pharmaceuticals detected, even those that are considered persistent to biological degradation, such as azithromycin, carbamazepine, and diclofenac. No significant differences were observed in the final specific methane production without graphene oxide and with the lowest graphene oxide concentration, yet the highest graphene oxide concentration partially inhibited methane production. The relative abundance of antibiotic resistance genes was not affected by the graphene oxide addition. Finally, significant changes in the microbial community including bacteria and archaea were detected with graphene oxide addition.

Fabrication of reduced graphene oxide-doped carbon aerogels from water hyacinth for removal of methylene blue in water and energy storage

The development of industries has caused severe impacts on the environment and increased the demand of using energy. In this work, reduced graphene oxide-doped water hyacinth carbon aerogels (rGO/WHCA) were synthesized by cross-linking cellulose with poly(vinyl alcohol) as a binder and addition of graphene oxide (GO) as rGO precursors, followed by freeze-drying and pyrolysis techniques. The obtained materials were studied for adsorption of methylene blue (MB) in water and applied as electrodes for the supercapacitor. The impact of GO content on the characteristics, adsorption performance, and electrochemical properties of the rGO/WHCA were investigated. Besides, the concurrent effects of the adsorption time, and MB concentration on the adsorption capacity were evaluated via the response surface methodology according to the Box–Behnken model. The obtained rGO/WHCA materials exhibited ultralow density, high porosity, and an abundance of meso- and micropores structures. Especially, rGO/WHCA materials showed a great ability for removing MB in water with the highest adsorption capacity up to 95.03 mg/g after 420 min with the initial MB concentration of 150 ppm at pH 9 and performed the electrical double-layer capacitors (EDLCs) in a three-electrode system with an outstanding specific capacitance of 272.08 F/g at current density of 0.5 A/g. The obtained results open a potential pathway of using biomass sources, like water hyacinth, for solving environmental issues and the demand for energy storage.

Effect of graphene oxide particle as nanomaterial in the production of engineered cementitious composites including superplasticizer, fly ash, and polyvinyl alcohol fiber

Graphene oxide (GO) is a desirable nanoparticle for strengthening composite material owing to its outstanding mechanical characteristics. This research examines the influence of graphene oxide (GO) on the mechanical characteristics of Engineered Cementitious Composites (ECCs), including their mechanical performance under tension and compression conditions. In this study, GO was utilized with different percentages like 0 %. 0.02 %, 0.04 %, 0.05 %, 0.06 %, 0.08 % and 0.10 % by the weight of cement for determining the compressive strength, direct tensile strength and modulus of elasticity of ECC mixture. However, the dry density is improving as the content of GO increases while the water absorption is getting reduced blended with GO as nanomaterials rises in the ECC mixture after 28 days correspondingly. It has been observed that the use of GO as nanomaterial up to 0.08 % in ECC mixture is providing optimum compressive strength, tensile strength and modulus of elasticity after 28 days respectively. The increased composite strength as well as the chemical connection formed by the introduction of GO between the polyvinyl alcohol (PVA) fiber and the cement matrix are both responsible for the excellent mechanical characteristics of the GO-reinforced ECC mixture.

Electron paramagnetic resonance

We have studied literature from investigation of the impact of Mechanothermal effects in the creation of defect structures in dispersed systems after prolonged mechanical treatment of ZnO powders. This work illustrates some potential applications of electron paramagnetic resonance. EPR application beginning of a variety of paramagnetic processes is based on the knowledge that this centre happens when some materials are mechanically treated. These facilities can act as EPR sondes of various thermal processes that appear when systems are being mechanically treated consisting of ZnO.Zn was evaporated in air, dry and humid argon flow, and dry and humid nitrogen flow to create Zno tetrapod nanostructures. SEM, X-ray diffraction, photoluminescence, photoluminescence excitation (PLE) spectroscopy (at various temperatures), and electron paramagnetic resonance (EPR) spectroscopy at −160 ℃ and room temperature have all been used to explore the characteristics. It is discovered that the fabrication conditions have a considerable impact on the acquired EPR and PL spectra. while some of the samples exhibit a g = 1.96 EPR signal. We used microwave processing to create and mix ZnO nanoparticles (ZnO-NPs) with various amounts of graphene oxide (GO) (10 %, 20 %, and 30 %).The process delivered evenly distributed ZnO-NPs onto and between the rGO layers.(GZCs). The UV–vis absorption, PL emission, defect states of the ZnO, EPR signals, photo-electrochemical reaction, and charge transfer properties were all influenced by the annealing temperature and graphene oxide content. The GZCs' HRTEM microscopy pictures revealed interpenetrating structures and vacancy flaws that were easily seen. The findings showed that following hybridization with GO, the defect sites (Zn interstitials, oxygen vacancy, ionised oxygen vacancy, and oxygen interstitials) greatly decreased. The GZC-10photo-conversion 10 %'s efficiency(ŋ= 13.1 × 10-3%) We have studied literature from Ref.[1]which show that.

Investigating the Extracellular-Electron-Transfer Mechanisms and Kinetics of Shewanella decolorationis NTOU1 Reducing Graphene Oxide via Lactate Metabolism

Microbial graphene oxide reduction is a developing method that serves to reduce both production costs and environmental impact in the synthesis of graphene. This study demonstrates microbial graphene oxide reduction using Shewanella decolorationis NTOU1 under neutral and mild conditions (pH = 7, 35 °C, and 1 atm). Graphene oxide (GO) prepared via the modified Hummers' method is used as the sole solid electron acceptor, and the characteristics of reduced GO (rGO) are investigated. According to electron microscopic images, the surface structure of GO was clearly changed from smooth to wrinkled after reduction, and whole cells were observed to be wrapped by GO/rGO films. Distinctive appendages on the cells, similar to nanowires or flagella, were also observed. With regard to chemical-bonding changes, after a 24-h reaction of 1 mg mL-1, GO was reduced to rGO, the C/O increased from 1.4 to 3.0, and the oxygen-containing functional groups of rGO were significantly reduced. During the GO reduction process, the number of S. decolorationis NTOU1 cells decreased from 1.65 × 108 to 1.03 × 106 CFU mL-1, indicating the bactericide effects of GO/rGO. In experiments adding consistent concentrations of initial bacteria and lactate, it was shown that with the increase of GO additions (0.5-5.0 mg mL-1), the first-order reaction rate constants (k) of lactate metabolism and acetate production increased accordingly; in experiments adding consistent concentrations of initial bacteria and GO but different lactate levels (1 to 10 mM), the k values of lactate metabolism did not change significantly. The test results of adding different electron transfer mediators showed that riboflavin and potassium ferricyanide were able to boost GO reduction, whereas 2,6-dimethoxy-1,4-benzoquinone and 2,6-dimethyl benzoquinone completely eliminated bacterial activity.