Synthesis Of GO Research Articles

Green synthesis of graphene-based derivatives from Ulva lactuca extract: Characterization and biomedical applications

Graphene-based materials have been extensively researched due to its biocompatibility, unique conjugated structure, and relatively low cost in the realm of biology. Graphene is increasingly being explored for many medical uses, including as DNA-hybridization devices, cancer treatment, and medicine administration. Furthermore, it exhibits substantial potential in several fields of biological applications, such as antibacterial interventions, therapy, and biosensing. The synthesis of GO and rGO was achieved in this work for the first-time using macroalgae, Ulva lactuca as a reducing agent. The antibacterial activity of graphene-based derivatives was evaluated against two different human pathogenic bacteria. Bacterial growth inhibition increased in proportion to the higher concentration. Higher concentration of nanosheets could enhance the cellular enzyme activity. Different scavenging assays are adapted to assess the antioxidant activity of GO and rGO. Significant in-vitro antioxidant activity was observed in a concentration-dependent manner. Furthermore, the antitumor activity of synthesized nanosheets was tested against human breast cancer cells (MCF-7) at various concentrations. The test results show that the graphene derivatives in the MCF-7 cell line exhibit an increase in apoptotic behaviour as sample concentration rises. This study could offer novel insights into the antibacterial, antioxidant, and anticancer activities of the green synthesized graphene-based derivatives.

Remediation of Safranin-O and acid fuchsin by using Ti3C2 MXene /rGo-Cu2O nanocomposite: Preparation, characterization, isotherm, kinetic and thermodynamic studies

In recent years, MXene has become one of the most intriguing two-dimensional layered (2Dl) materials extensively explored for various applications. In this study, a Ti3C2 MXene/rGo-Cu2O Nanocomposite (TGCNCs) was developed to eliminate Safranin-O effectively (SO) and Acid Fuchsin (AF) as cationic dyes from the aquatic environment. Multistep was involved in the preparation of the adsorbent system, including the Preparation of Ti3C2, after that, GO synthesis by the Humer method, followed by rGO production, then added CuSO4 to obtain a final Nanocomposite (NCs) called “TGCNCs”. The structure of TGCNCs can be varied in several ways, including FTIR, SEM, TGA, Zeta, EDX, XRD, and BET, to affirm the efficacious preparation of TGCNCs. A novel adsorbent system was developed to remove SO and AF, both cationic dyes. Various adsorption conditions have been optimized through batch adsorption tests, including the pH of the solution (4–12), the effect of dosage (0.003–0.03 g), the impact of the contact time (5–30 min), and the effect of beginning dye concentration (25–250 mg/L). Accordingly, the TGCNCs exhibited excellent fitting for Freundlich isotherm mode, resulting in maximum AF and SO adsorption capacities of 909.09 and 769.23 mg g−1. This research on adsorption kinetics suggests that a pseudo-second-order (PSO) model would fit well with the experimental data (RSO2 = 0.998 and RAF2 = 0.990). It is evident from the thermodynamic parameters that adsorption is an endothermic process that is spontaneous and favorable. During the adsorption of SO and AF onto NCs, it is hypothesized that these molecules interact intramolecularly through stacking interactions, H-bond interactions, electrostatic interactions, and entrapment within the polymeric Poros structure nanocomposite. Regeneration studies lasting up to five cycles were the most effective for both organic dyes under study.

Exploring the antimicrobial potential of biogenically synthesized graphene oxide nanoparticles against targeted bacterial and fungal pathogens

Abstract Graphene oxide (GO) and reduced graphene oxide (rGO) nanoparticles were synthesized using 40 mL of lemon juice extract as a reducing agent. The synthesized nanoparticles were characterized using various analytical techniques, including UV–visible spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The results confirmed the successful synthesis of GO and rGO nanoparticles with varied sizes and shapes. The synthesized nanoparticles were tested for their antimicrobial activity against a range of bacterial and fungal strains, including Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Candida albicans, Fusarium oxysporum, and Aspergillus flavus. Multiple concentrations of GO and rGO nanoparticles were tested, and it was observed that 100 µg·mL−1 of both GO and rGO showed the highest inhibitory effect against bacterial and produced zones of inhibition of 17.66 mm, 18.67 mm, and 17.88 for E. coli, S. aureus, K. pneumoniae and 20.33, 22.45, and 21.34 mm for C. albicans, F. oxysporum, and A. flavus. Comparatively, GO performed well as compared to rGO regarding antimicrobial activity. The synthesized nanoparticles exhibited significant antimicrobial activity against various bacterial and fungal strains and have the potential to be developed as novel antimicrobial agents.

New insight into interference-free and highly sensitive dopamine electroanalysis

Early diagnosis of Parkinson's disease and hyperprolactinemia based on electrochemical dopamine (DA) sensing appears as an efficient and promising practical diagnostic method. However, the coexistence of DA in real samples with ascorbic acid (AA) and uric acid (UA), which oxidize at potentials close to its own, prevents the accurate electrochemical DA sensing and therefore, hinders the effective diagnosis of these diseases. In this work, we successfully combined the electrostatic proprieties of GO, the electron transfer properties of an AuNPs@MWCNTs nanocomposite and the ability of thiol group of the amino acid l-cysteine to react chemically with carbonyl groups of UA, to develop a novel approach that enabled complete suppression of interference from AA and UA and hence, accurate DA electroanalysis in the conditions close to those of human blood serum. The chemical reaction between l-cysteine and UA was evidenced by monitoring the DPV responses of UA under different conditions. XRD, Raman spectroscopy, XPS and FE-SEM revealed the successful synthesis of GO and AuNPs@MWCNTs. The study of the electrode material (GO-AuNPs@MWCNTs) morphology via FE-SEM and HR-TEM showed that AuNPs@MWCNTs are distributed throughout the exfoliated GO layers. The fabricated sensor was calibrated in the concentration range of 0.5–5 μM, in the presence of the highest blood concentrations of AA and UA for healthy individuals. A linear relationship was observed and the LOD was found to be 1.31 nM (S/N = 3). Furthermore, the sensor showed good electron transfer kinetics, good repeatability and reproducibility, satisfactory long-term stability, and recoveries in human blood serum.

Study of the structure of graphene oxide obtained by oxidation of intercalated graphite compound by Raman light scattering method

This work shows the strategy of GO synthesis from intercalated graphite compound, rotation of the synthesis conditions was carried out, and the starting material and synthesis products were characterized in detail by a complex of physical and chemical methods: scanning electron microscopy, transmission electron microscopy, atomic force microscopy, Raman spectroscopy, and high-temperature catalytic oxidation. It was found by Raman spectroscopy that the initial IGC sample is a graphite structure with a low content of defects in graphene layers. Oxidation of this sample leads to a gradual increase in the measure of disordered carbon framework. One of the reasons for this is a decrease in the size of graphite-like crystallites with subsequent reorientation in the space of graphene layers. It has been established by a complex of physicochemical methods of research that the oxidation of IGC graphite with increasing oxidation time leads to an increase in the defectivity of the initial carbon framework due to a decrease in the linear size of carbon crystallites. When a certain reaction time is reached, the initial structure of the sample changes, and there is a partial reorientation of the crushed graphite-like fragments with a simultaneous increase in the number of defects.

Efficient lubrication of alkylated reduced graphene oxide based on tribochemistry

Graphene has been applied to the research of new lubricant additives in the field of tribology because of its excellent properties. However, during the mixing process of graphene and base oil, agglomerated structures are formed due to their incompatibility, and this phenomenon limits the full play of its advantages. In the face of this challenge, this paper designs a simple and efficient octadecyltriethoxysilane modified reduced graphene oxide (rGOOES) nanolubricant through a three-step process, including the synthesis, functionalization, and chemical reduction of GO, to meet the future needs of oil-based interface lubrication. The morphological and structural characteristics of rGOOES nanosheets were studied by scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier infrared spectroscopy and thermal weight loss analyzer, and the dispersion stability and tribological properties of rGOOES nanofluids were investigated by particle size distribution method and four-sphere method, respectively. According to the findings, the outcomes demonstrated that the procedure had the ability to augment the stability of rGOOES nanosheets’ dispersion and ensured their uninterrupted delivery to the contact interfaces of the steel ball friction pairs. Macro tribological experiments confirmed that the blend with rGOOES (0.01 wt%) exhibited significant friction and wear reduction compared to the base oil, reducing the coefficient of friction by 22.1% and the wear scar diameter by 24.8% of the steel ball friction pairs. The mechanism analysis indicated that this improvement in lubrication properties was attributed to the high dispersion of rGOOES nanosheets and the reorganization of the sliding interfaces, as well as the protective film formed on the friction interfaces of the steel balls. Thus, this work provides a practical application of two-dimensional nanomaterials in the field of lubrication.

Enhancing mercury (II) ion detection with graphene oxide-cerium oxide nanocomposites: Enzyme free ultrasensitive detection

This study discusses how gold (Au) electrodes were modified by immobilizing graphene oxide-cerium oxide (GO-CeO2) nanocomposite to detect mercury (II) (Hg2+) ions selectively. The GO-CeO2 nanocomposite was prepared using the sonochemical method after synthesis of GO through a modifier Hummers’ method and CeO2 via a coprecipitation technique. The structural, morphological, and optical characteristics of the nanocomposite were assessed using X-ray diffraction (XRD), transmission electron microscopy (TEM), and diffuse reflectance spectroscopy (DRS), respectively. Cyclic voltammetry (CV) provided the selective electrochemical response for Hg2+ among different divalent metallic ions. Scan rates (ranging from 5 to 300 mV/s) confirmed the stability of the modified electrode. It was suggested that the Hg2+ ion and modified Au electrode interacted through both diffusion-controlled and surface-controlled mechanisms, with diffusion-controlled interaction being the dominant one. Differential pulse voltammetry (DPV) was chosen to assess sensitivity by conducting concentration profiles in the range of 10 fM to 1 mM. The calculation yielded a limit of detection of 1.87 fM (fM). The developed sensor represents a promising platform for the ultrasensitive detection of Hg2+ ions.

Conversion of palm oil empty fruit bunches to highly stable and fluorescent graphene oxide quantum dots: An eco-friendly approach

Empty fruit bunches, a byproduct of palm oil mills, are currently underutilized despite their potential as a valuable source of biomass for material development. A novel and sustainable method is proposed in this work to produce graphene oxide quantum dots (GOQDs) using empty fruit bunches (EFB) as a starting material. Carbonization of EFB was conducted in a nitrogen atmosphere furnace at temperatures ranging from 30 to 750 °C with a constant heating rate of 10 °C/min, followed by synthesis of GO from the carbonized cellulose using the modified Hummers' method. Subsequently, hydrothermal treatment was employed to synthesize GOQDs from GO, resulting in highly stable and fluorescent GOQDs with an average diameter size of 6.80 nm. The optical properties of GOQDs were characterized by UV–vis spectroscopy, which exhibited a strong absorption at 230 nm, yellow color under visible light, and blue-green luminescence under a 395 nm UV lamp. FTIR spectra confirmed the existence of hydroxyl, carbonyl, and hydrocarbon groups, which originated from lignocellulosic materials and provided excellent water stability and solubility properties to GOQDs. The current study presents an eco-friendly approach to converting biomass waste into materials with outstanding chemical and physical properties that can be applied in various fields.

Green synthesis of reduced graphene oxide by shallots

An environment-friendly and low-cost green reducing agent shallots are used for the facile and effective synthesis of partially reduced Graphene Oxide (prGO). The improved hummers method is used for the synthesis of GO. Synthesis of reduced graphene oxide (rGO) using green reducing agents is recognized as one of the most economical, environmentally friendly, facile and efficient approaches. At the same time, partially reduced graphene oxide have the advantages and convenience of both GO and rGO and can be facilitated for more advanced applications. X-Ray Diffraction, RAMAN spectroscopy, SEM, UV Visible and FTIR spectroscopy are used for the analysis of structural and surface properties of prGO. FTIR analysis established that most of the oxygen-containing functional groups such as hydroxyl, carboxyl carbonyl, and epoxy groups are removed partially during the reduction process. XRD peak is observed at 2θ = 22.5°, and ID/IG ratio in Raman spectra is about 0.92. From all the above studies we got clear information regarding the facile and effective partial reduction of graphene oxide using shallots.

Preliminary Study on Preparation of Deproteinized Natural Rubber/Graphene Oxide Nanocomposite

Deproteinized natural rubber/graphene oxide (DPNR/GO) nanocomposite was prepared and characterized in the present work. GO was synthesized by oxidation process via Hummer modified method, and it was characterized with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR), and water contact angle. The presence of hydrophilic functional groups in GO sheet was confirmed by FT-IR, NMR and water contact angle. The characteristic XRD scattering pattern of GO was observed at about 2θ= 9.5° and it confirmed the successful synthesis of GO. The GO was incorporated into DPNR via graft copolymerization using tetraethylenpentamine/tert-butyl hydroperoxide as redox initiators. The DPNR/GO nanocomposites with 0.1, 0.5, and 1.0 phr of GO were fabricated and characterized through FTIR, tensile strength, and scanning electron microscope. The stress at break of DPNR/GO nanocomposite increased when the GO suspension was homogenized before the graft copolymerization. The GO content is found to increase the stress at break for the nanocomposite; however, the hardness of the nanocomposite did not change at high GO loading. The result indicated that the formation of nanocomposite materials between natural rubber and GO was affected by the sheet morphology and hydrophilicity of GO.

Graphene Oxide-PAMAM Nanocomposite and Ionic Liquid Modified Carbon Paste Electrode: An Efficient Electrochemical Sensor for Simultaneous Determination of Catechol and Resorcinol.

In this paper, a simple strategy was proposed for the analysis of catechol by a carbon paste electrode (CPE) modified with graphene oxide-third generation of poly(amidoamine) dendrimer (GO/G3-PAMAM) nanocomposite and ionic liquid (IL). The synthesis of GO-PAMAM nanocomposite was confirmed using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared spectroscopy (FT-IR) techniques. The prepared modified electrode (GO-PAMAM/ILCPE) exhibited good performance to detect catechol with a notable decrease in overpotential and increase in current compared with an unmodified CPE. Under optimum experimental conditions, GO-PAMAM/ILCPE electrochemical sensors indicated a lower limit of detection (LOD) of 0.034 μM and a linear response in the concentration range of 0.1 to 200.0 µM for the quantitative measurement of catechol in aqueous solutions. In addition, GO-PAMAM/ILCPE sensor exhibited an ability to simultaneously determine catechol and resorcinol. It can be found that catechol and resorcinol could be completely separated on the GO-PAMAM/ILCPE with the differential pulse voltammetry (DPV) technique. Finally, a GO-PAMAM/ILCPE sensor was utilized to detect catechol and resorcinol in water samples with recoveries of 96.2% to 103.3% and relative standard deviations (RSDs) of less than 1.7%.

The potential of microalgae Dunaliella salina to treat shrimp pond wastewater in a PAN/GO membrane bioreactor

Graphene has attracted a significant amount of attention because to its excellent mechanical, electrical, thermal, and optical characteristics. In this work, a membrane bioreactor with hollow fibre PAN/GO nanocomposite was studied for the treatment of Persian Gulf shrimp pond wastewater. Dunaliella salina microalgae have been used for better treatment and the formation of sludge mass in a shorter period of treatment in the MBR system. Additionally, GO nanoparticles were used in order to improve the hydrophilicity of the membranes. Various tests, such as Pure water permeate (PWP), X-ray diffraction spectroscopy (XRD), Atomic force microscopy (AFM), Dynamic light scattering (DLS), Contact angle (CA), Scanning electronic microscopy (SEM), Fourier transform infrared substances (FTIR) were used to characterize the synthesized membranes. To evaluate the treated wastewater, several factors were evaluated, including: TP, TN, TSS, NTU, BOD, COD, EC. The contact angle was reduced by the inclusion of GO nanoparticles from 53.8° for PAN-0 to 45.4° for PAN-3. The results of FTIR analysis confirmed the synthesis of GO and showed the formation of different deposits as fouling on the surface of the prepared membranes after MBR process. Also, the removal percentage of COD and BOD5 was over 90% for membranes with graphene oxide nanoparticles. The turbidity for all fabricated membranes were removed ∼98%. Also, very little fouling occurred in the membranes constructed with GO membranes and the maximum concentration of GO let to maximum performance regarding to the high potential of fouling control. In addition, the growth of Microalgae Dunaliella salina with shrimp wastewater was observed successfully. In conclusion, the finding of this work not only proposed a promising solution for controlling fouling in an MBR but also resulted in a benefit product, i.e. microalgae Dunaliella salina.

Graphene oxide dispersion in epoxy resin prepared by direct phase transfer from ethanol: Rheology and aging

Graphene oxide addition to epoxy still presents challenges related to attaining optimized dispersion in scale-up production. Herein, the synthesis of high-quality GO by exfoliation in ethanol enabled the spontaneous phase transfer of GO from solvent to epoxy resin to produce a masterbatch with 1.5 wt.% GO content. Nanocomposites with 0.25 wt.%, 0.50 wt.% and 0.75 wt.% nanofiller contents were obtained by masterbatch dilution in epoxy resin. The results reveal the presence of a partial cross-linked network in these nanocomposites associated with the presence of GO, even without the use of a hardener. Thermogravimetric analysis showed the influence of GO on the oxidative decomposition mechanism of epoxy resin, whose behavior was assigned to strong interactions in the GO-epoxy interphase. Furthermore, the rheological behavior changes demonstrate the high quality of the GO dispersion in the resin obtained in this work. The nanocomposites showed high viscosity increases over time and pseudoplastic behavior, which was completely different from the neat epoxy resin. Aged nanocomposites without hardener present a first chemically cross-linked layer of epoxy to GO (∼ 10% for nanocomposite at 0.50 wt.% GO content) and a supramolecular coating interacting and entangled with these structures (> 40% of epoxy chains for EP-GO50).

Efisiensi Counter Electrode Dengan Pengurangan Pemakaian Platina Menggunakan Komposit Bahan Ramah Lingkungan Grafin Dan Carbon Nanotubes Untuk Aplikasi Dye Sensitized Solar Cells

<p><span lang="EN-AU">Dye sensitized solar cells (DSSCs) are the most popular solar cells in the third generation. DSSCs have been widely developed as an alternative to silicon-based solar cells because of its easy manufacturing process, high efficiency, easy production costs, and environmental friendliness. Graphene and carbon nanotubes (CNTs) are promising materials to reduce the use of platinum (Pt) in counter electrode (CE) due to their excellent properties, such as thermal, electrical conductivity, and high surface area. One of the derivatives of graphene that is often used is reduced graphene oxide (rGO) which is produced from GO solution by a reduction process. GO was synthesized in an electrolyte containing surfactant by the electrochemical exfoliation method. The specially prepared sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-silphonate (TC14) surfactant was used in GO synthesis. The CE thin film of TC14-rGO/CNTs/Pt hybrid shows the highest efficiency values (0.0594%) with Jsc, Voc, and FF of 0.176 mA/cm2, 0.622 V, and 0.464, respectively. This was believed due to the conjugated network in CNTs acts as a connecting cable between the TC14-rGO layers and as a vacancy filler, the high electrical conductivity value and the larger surface area also cause faster electron movement, making these properties important in DSSC performance. The FF value which is also the highest in the TC14-rGO/CNTs/Pt hybrid samples as CE is also influenced by its structure. The high surface area of CNTs and TC14-rGO in the TC14-rGO/CNTs/Pt hybrid samples exhibited important properties for generating dye after electron injection and led to a faster route of electron regulation during DSSCs processing. These findings indicate that Pt composited with environmentally friendly and inexpensive materials such as T14-rGO and CNTs can improve CE performance in DSSCs applications. Based on this, this research can be used as a basis for further research on the fabrication of carbon-based CE</span></p>

Synthesis and characterization of nanostructured ternary composites of graphene oxide/Fe3O4/NiO for waste water treatment

Photocatalysis using solar energy and semiconductors is widely used in the purification of air and the processing of wastewater. Present study deal with cost-effective GO synthesis, supporting NiO/Fe3O4 ternary nanocomposites; for the rapid photocatalytic degradation of the Rhodamine B Dye. For this purpose, nickel oxide nanoparticles and iron oxide nanoparticles were synthesized by hydrothermal method. Synthesis of graphene oxide was done by using modified hummers method. These trimetallic nanoparticles were characterized by FTIR (Fourier Transform Infrared Spectroscopy), Scanning Electron Microscopy (SEM) and X-ray Diffraction Crystallography (XRD) for structure, shape and composition determination. The photocatalytic degradation of Rhodamine B dye was conducted and various parameters like catalyst amount, dye concentration, pH and contact time optimization were performed to evaluate dye degradation efficiency of Fe3O4/NiO/Graphene trimetallic nanoparticles. Kinetic models were studied to check degradation rate and Pseudo 1st order kinetic model was most suitable to the experimental data of dye degradation.

Sustainable development of manganese sulfoselenide nanoparticles anchored graphene oxide nanocomposite for high-performance supercapacitor and lithium-ion battery applications

Transition metal chalcogenides have been described as promising electrode materials for supercapacitors due to their low electronegativity, suitable electrical conductivity, comparatively higher specific capacitance, and favorable electrochemical redox regions. However, the poor electrical conductivity and substantial volume fluctuations provide a significant obstacle to industrial use. A new method to develop metal incorporated GO at the time of GO synthesis and subsequent conversion to metal sulfoselenides is proposed and demonstrated here. This novel process incorporates the advantages of both GO and the metal sulfoselenides for electrochemical energy storage applications. The average size of the nanoclusters was 52 nm as identified by Transmission electron microscopy. As pseudocapacitive electrode GO-MnSSe delivered a specific capacitance of 603 F/g at 0.1 A/g in 1 M KCl of aqueous electrolyte, because of their distinct and stable form. The fabricated 2-electrode device showed a specific capacitance of 98.5 mF/cm2 at 80 µA/cm2, showing good retention of 67 % at the end of the 9000 cycles. As Li-ion battery half-cells, at specific currents of 50, 100, 250, and 500 mA/g, GO-MnS delivered a capacity of 587, 378, 273, and 211 mA h/g respectively, reflecting a retention rate of 64 %, while the specific current was increased 10 times. The initial capacity of GO-MnS and GO-MnSSe at 100 mA/g was 494 and 495 mAh/g respectively, and for GO-MnS and GO-MnSSe at 250 mA/g the delivered capacity values were 376 and 363 mA h/g respectively. Coulombic efficiency (CE) for GO, GO-SW (single wash), GO-MnS, and GO-MnSSe were 99.52 %, 99.6 %, 98.7 %, and 99 % respectively at the end of the 100 cycles. Moreover, GO-MnS were cycled at a higher rate of 500 mA/g for 500 cycles which showed a decay initially nevertheless it stabilized after few cycles and showed a retention of 88 % at the end of 500 cycles from 20th cycle. The ex-situ morphological analysis of GO-MnS were conducted as well as the kinetic of the electrode were studied by before and after cycling EIS measurement. As part of this, as an anode for lithium-ion batteries, high Li-ion storage capacity and cyclic stability were observed.

Synthesis, Characterization and Applications of GO–TiO2 Nanocomposites in Textile Dye Remediation

Synthesis, Characterization and Applications of GO–TiO2 Nanocomposites in Textile Dye Remediation

Thin layer of nano nomposite RGO COMOS as a counter electrode on Dye Sensitized Solar Cell (DSSC)

This research aims to synthesis of GO using the Hummer method and the effect of adding CoS(Cobalt Sulfide) and CoMoS(Cobalt Molybdenum Sulfide) Nano composites to RGO as a counter electrode of DSSC. RGO doped CoMoS and RGO doped CoMoS was synthesis using solvothermal method by adding nanocomposite CoS and CoMoS to GO by heating 200˚C. RGO CoMoS powder was formed into a paste by stirring and adding a polymer binder. The paste was deposited onto the FTO glass substrate by the slip casting method so that a thin sheet was obtained on the substrate and applied as a counter electrode on the DSSC. This composite will be measured and tested for the morphology of its layer using SEM and tested for electrical properties with Keithley I-V meter. The additional of CoS and CoMoS may cause the changes crystal size of RGO. RGO CoMoS has higher efficiency than GO and RGO. Thin film of RGO CoMoS can be used of counter electrode DSSC that has Voc= 0,39volt, fill factor (FF) 34,32% and η= 1,54%.

A DFT theoretical and experimental study about tetracycline adsorption onto magnetic graphene oxide

This work reports the study of tetracycline adsorption on magnetic graphene oxide (GO·Fe3O4) from theoretical and experimental approaches. From the theoretical side, the combination of ab initio and Density Functional Theory (DFT) presents the structural and electronic properties of magnetic nanoadsorbent and tetracycline, revealing chemical adsorption between tetracycline and GO·Fe3O4. From the experimental viewpoint, the synthesis of GO·Fe3O4 was performed via co-precipitation method with control of magnetite (Fe3O4) incorporation on the GO surface. The nanoadsorbents were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The maximum tetracycline adsorption capacity was 531.93 mg g−1 using 50 mg of GO·Fe3O4 1:1, with an initial concentration of TC (1000 mg L−1), pH 7.0 at 293 K. The thermodynamic parameters showed that the process was spontaneous, exothermic, and chemical. Theoretical and experimental studies were coherent and showed that tetracycline adsorption on GO·Fe3O4 occurs by chemisorption mechanism. In summary, magnetic nanoadsorbent (GO·Fe3O4 1:1) proves to be an efficient nanomaterial for removing tetracycline from aqueous solutions, excluding subsequent process steps.

Li/graphene oxide primary battery system and mechanism

AbstractA novel type of Li/graphene oxide (Li/GO) battery based on a spontaneous redox reaction between Li metal and GO cathode is introduced as an alternative viable primary battery system. Here, we present an efficient synthesis of GO by the modified Hummers method and focus on a comprehensive study of the reduction mechanism. The Li/GO battery was thoroughly analyzed by various physical and electrochemical methods. GO rich in oxygen‐bearing functional groups on graphene layers provided lithium storage sites and delivered a high discharge capacity of around 720 mAh/g at 12 mA/g. Products formed on the surface during reduction were analyzed, and a mechanism was proposed. The results uncovered the reasons underlying the improved electrochemical properties and the contribution of the irreversible capacity of reduced GO in graphene‐based composite electrode materials for metal‐ion batteries. The Li/GO concept is expected to shed light on the design of similar M/GO batteries based on other active metal anodes (e.g., M = Na, Mg, Al, Zn).