scholarly journals Construction of Sandwich-like Structured GO/Cu2O/GO Electrochemical Biosensor for Sensitive Detection of H2O2 Releasing from Living Cells

2020 ◽  
Author(s):  
Donghang Yin ◽  
Junyan Tang ◽  
Ruixue Mo ◽  
Fei Wang ◽  
Xiuzhi Jia ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Indium Tin Oxide ◽  
High Performance ◽  
Limit Of Detection ◽  
A549 Cells ◽  
X Ray Diffraction ◽  
Long Term Stability ◽  
Transmission Electron ◽  
Ito Glass

Abstract A well-designed sandwich-like structure based on Cu2O nanocubes sandwiched between graphene oxide (GO) buffer layer was fabricated on indium tin oxide (ITO)/glass substrate via drop-casting method. The sandwich-like morphologies, GO/Cu2O/GO/ITO structures, were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) measurements. Electrochemical studies demonstrated the fact that GO/Cu2O/GO/ITO electrode revealed the superior electro-catalytic activity and electrical conductivity as a result of the introduction of graphene oxide and formation of sandwich-like structures, which effectively improved the electrical performances of Cu2O-based sandwich structure in H2O2 detection. The proposed sandwich-like GO/Cu2O/GO/ITO sensor was experimentally optimized and displayed a widespread linear response in the range from 0.25 μM to 20 mM with a low limit of detection (LOD) of 0.2 μM (S/N=3) in H2O2 sensing. Besides achieving acceptable selectivity, excellent reproducibility, and long-term stability of sandwich-like lamellar structures, GO/Cu2O/GO/ITO sensor exhibited high performance in detecting H2O2 released from A549 cells. Therefore, the novel sandwich-like GO/Cu2O/GO/ITO sensor provides an economical, potent and high-throughput platform for detecting various species involving H2O2-generation reactions for biomedical applications.

scholarly journals Ce-Doped PANI/Fe3O4 Nanocomposites: Electrode Materials for Supercapattery

2021 ◽  
Vol 3 ◽  
Author(s):  
Subash Pandey ◽  
Shova Neupane ◽  
Dipak Kumar Gupta ◽  
Anju Kumari Das ◽  
Nabin Karki ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrode Material ◽  
High Performance ◽  
Electrode Materials ◽  
Specific Capacity ◽  
Maximum Energy ◽  
Potential Range ◽  
X Ray Diffraction ◽  
Active Electrode ◽  
Transmission Electron

In this study, we report on a combined approach to preparing an active electrode material for supercapattery application by making nanocomposites of Polyaniline/Cerium (PANI/Ce) with different weight percentages of magnetite (Fe3O4). Fourier-transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) analyses supported the interaction of PANI with Ce and the formation of the successful nanocomposite with magnetite nanoparticles. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses showed the uniform and porous morphology of the composites. Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) were used to test the supercapattery behavior of the nanocomposite electrodes in 1.0 M H2SO4. It was found that the supercapattery electrode of PANI/Ce+7 wt.% Fe3O4 exhibited a specific capacity of 171 mAhg−1 in the potential range of −0.2 to 1.0 V at the current density of 2.5 Ag−1. Moreover, PANI/Ce+7 wt.% Fe3O4 revealed a power density of 376.6 Wkg−1 along with a maximum energy density of 25.4 Whkg−1 at 2.5 Ag−1. Further, the cyclic stability of PANI/Ce+7 wt.% Fe3O4 was found to be 96.0% after 5,000 cycles. The obtained results suggested that the PANI/Ce+Fe3O4 nanocomposite could be a promising electrode material candidate for high-performance supercapattery applications.

scholarly journals Synthesis of Polyaniline coated Graphene Oxide @ SrTiO3 Nanocube Nanocomposites for Enhanced Removal of Carcinogenic Dyes from Aqueous Solution

2016 ◽  
Author(s):  
Syed Shahabuddin ◽  
Norazilawati Muhamad Sarih ◽  
Muhammad Afzal Kamboh ◽  
Hamid Rashidi Nodeh ◽  
Sharifah Mohamad
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Methylene Blue ◽  
Graphene Oxide ◽  
Methyl Orange ◽  
Oxidative Polymerization ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Polymerization Method

The present investigation highlights the synthesis of polyaniline (PANI) coated graphene oxide doped with SrTiO3 nanocube nanocomposites through facile in-situ oxidative polymerization method for the efficient removal of carcinogenic dyes, namely, the cationic dye methylene blue (MB) and the anionic dye methyl orange (MO). The synthesised nanocomposites were characterised by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The adsorption efficiencies of graphene oxide (GO), PANI homopolymer and SrTiO3 nanocubes-doped nanocomposites were assessed by monitoring the adsorption of methylene blue and methyl orange dyes from aqueous solution. The adsorption efficiency of nanocomposites doped with SrTiO3 nanocubes were found to be of higher magnitude as compared with undoped nanocomposite. Moreover, the nanocomposite with 2 wt% SrTiO3 with respect to graphene oxide demonstrated excellent adsorption behaviour with 99% and 91% removal of MB and MO respectively, in a very short duration of time.

Synthesis of Trilaminar Core–Shell Au/α-Fe2O3@SnO2Nanocomposites and their Application for Nonenzymatic Dopamine Electrochemical Sensing

NANO ◽  
2019 ◽  
Vol 14 (11) ◽  
pp. 1950138 ◽  
Author(s):  
Sai Zhang ◽  
Shijun Yue ◽  
Jiajia Li ◽  
Jianbin Zheng ◽  
Guojie Gao
Keyword(s):  
Electron Microscopy ◽  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Synthesis Process ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Term Stability ◽  
Transmission Electron

Au nanoparticles anchored on core–shell [Formula: see text]-Fe2O3@SnO2 nanospindles were successfully constructed through hydrothermal synthesis process and used for fabricating a novel nonenzymatic dopamine (DA) sensor. The structure and morphology of the Au/[Formula: see text]-Fe2O3@SnO2 trilaminar nanohybrid film were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical properties of the sensor were investigated by cyclic voltammetry and amperometry. The experimental results suggest that the composites have excellent catalytic property toward DA with a wide linear range from 0.5[Formula: see text][Formula: see text]M to 0.47[Formula: see text]mM, a low detection limit of 0.17[Formula: see text][Formula: see text]M (S/[Formula: see text]) and high sensitivity of 397.1[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text]. In addition, the sensor exhibits long-term stability, good reproducibility and anti-interference.

scholarly journals Reduced Graphene Oxide–Epoxy Grafted Poly(Styrene-Co-Acrylate) Composites for Corrosion Protection of Mild Steel

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 666
Author(s):  
Xinchuan Fan ◽  
Yue Hu ◽  
Yijun Zhang ◽  
Jiachen Lu ◽  
Xiaofeng Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
Corrosion Properties ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Scanning Electron

Reduced graphene oxide–epoxy grafted poly(styrene-co-acrylate) composites (GESA) were prepared by anchoring different amount of epoxy modified poly(styrene-co-acrylate) (EPSA) onto reduced graphene oxide (rGO) sheets through π–π electrostatic attraction. The GESA composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The anti-corrosion properties of rGO/EPSA composites were evaluated by electro-chemical impedance spectroscopy (EIS) in hydroxyl-polyacrylate coating, and the results revealed that the corrosion rate was decreased from 3.509 × 10−1 to 1.394 × 10−6 mm/a.

scholarly journals Structural Characterization of Graphene Oxide: Surface Functional Groups and Fractionated Oxidative Debris

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1180 ◽  
Author(s):  
Elvin Aliyev ◽  
Volkan Filiz ◽  
Muntazim M. Khan ◽  
Young Joo Lee ◽  
Clarissa Abetz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Functional Groups ◽  
Structural Model ◽  
Oxide Surface ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
Surface Functional Groups ◽  
X Ray ◽  
Transmission Electron

The purpose of this work is the structural analysis of graphene oxide (GO) and by means of a new structural model to answer the questions arising from the Lerf–Klinowski and the Lee structural models. Surface functional groups of GO layers and the oxidative debris (OD) stacked on them were investigated after OD was extracted. Analysis was performed successfully using Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), X-ray photoemission spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, solid-state nuclear magnetic resonance spectroscopy (SSNMR), standardized Boehm potentiometric titration analysis, elemental analysis, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The analysis showed that graphene oxide layers, as well as oxidative debris contain different functional groups such as phenolic –OH, ketone, lactone, carboxyl, quinone and epoxy. Based on these results, a new structural model for GO layers is proposed, which covers all spectroscopic data and explains the presence of the other oxygen functionalities besides carboxyl, phenolic –OH and epoxy groups.

Synthesis and Photocatalytic Activity of Visible-Light Responsive BiOBr/GO Composites

2017 ◽  
Vol 751 ◽  
pp. 807-812
Author(s):  
Tuangphorn Prasitthikun ◽  
X. Wu ◽  
Tsugio Sato ◽  
Charusporn Mongkolkachit ◽  
Pornapa Sujaridworakun
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Visible Light ◽  
High Efficiency ◽  
Precipitation Method ◽  
Mixed Solution ◽  
Diffuse Reflection Spectroscopy ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Photocatalytic Activities

High efficiency BiOBr/GO composites photocatalyst were successfully synthesized via a facile precipitation method. The precursors were prepared by dissolving Bi (NO3)3.5H2O and KBr in glycerol and distilled water, respectively. Various amounts (0.1-2 wt%) of graphene oxide were added into the mixed solution precursors, and stirred at room temperature to get precipitated powder without further heat treatment. The obtained products were characterized for phase, morphology, optical properties and surface area by X-ray diffraction (XRD), transmission electron microscopy (TEM), filed-emission scanning electron microscopy (FE-SEM), UV-Vis diffuse reflection spectroscopy (DRS) and Brunauer–Emmett–Teller (BET), respectively. The morphology and structure of as-synthesized samples were composed of numerous fine plates of BiOBr dispersed on the GO sheets. The photocatalytic activities of BiOBr/GO composites were evaluated by rhodamine B degradation under visible light irradiation. As the results, the significant increase in photodegradation of BiOBr/GO composite comparing with pure BiOBr was observed. Among all samples, the composite with 1 wt% of graphene oxide showed the highest photocatalytic performance.

scholarly journals Electrodeposition and Characterization of Mesoporous Nanostructured Cobalt Films using Brij78 Templated

2015 ◽  
Vol 18 (3) ◽  
pp. 165-168 ◽  
Author(s):  
M. A. Ghanem ◽  
I. S. El-Hallag
Keyword(s):  
Electron Microscopy ◽  
High Performance ◽  
Electrode Materials ◽  
X Ray Diffraction ◽  
Uniform Size ◽  
Cobalt Films ◽  
Transmission Electron ◽  
Ordered Mesoporous ◽  
Mesoporous Thin Films

In this manuscript the preparation of highly ordered mesoporous cobalt films containing close packed arrays of spherical holes of uniform size was demonstrated by electrochemical deposition using the hexagonal liquid crystal template (H1-e Co). The template used was Brij®78 surfactant. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), voltammetric methods, and low angle X-ray diffraction (XRD) were used to characterize the electrodeposited mesopores films. Cyclic voltammetry (CV) technique are used to show the mesoporous thin films are promising to be used as electrode materials of high - performance super capacitors.

scholarly journals Synthesis and characterization of graphene oxide flakes for transparent thin films

2021 ◽  
Vol 22 (3) ◽  
pp. 595-601
Author(s):  
R.G. Abaszade ◽  
S.A. Mamedova ◽  
F.G. Agayev ◽  
S.I. Budzulyak ◽  
O.A. Kapush ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Indium Tin Oxide ◽  
Electromagnetic Interference ◽  
Large Scale ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

We have synthesized large scale, thin, transparent graphene oxide (GO) flakes by Hummer’s method and investigated their suitability for fabrication of transparent nanocomposites. The GO flakes were comprehensively characterized by X-ray diffraction, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), Raman spectroscopy and Differential Scanning Calorimetry (DSC). X-ray diffraction displayed the peak of graphene oxide at 9°degree, which is characteristic peak of GO in agreement with the literature results. Scanning Electron Microscopy images revealed that thin, transparent, flake form GO with 14,8 µm lateral size and 0,31µm thickness were synthesized. The comparison with literature results show that for the first time, our group could synthesize large scale, thin and more transparent GO flakes by simple Hummer’s method using simple dispersed graphite. EDX measurements indicate the formation of layered structure with oxygen containing functional groups. The intensity ratio between D and G peaks in the Raman spectra proves that less defective GO flakes have been synthesized. The solution ability of the synthesized material indicate that high quality GO flakes were synthesized, which make them effective soluble material due to oxygen containing groups formed on the graphene plane during synthesis process.DSC results shows that these flakes are thermally stable till 200°C.  Due to high solubility properties, large scale and transparency they can be very useful in fabrication of high optical transparent nanocompoties for replacement indium tin oxide transparent conductors in solar panels, biomedical applications and microwave absorbers for electromagnetic interference (EMI) environmental protection.

Changing width bandgap of TiO2 nanoparticles incorporating GO

MRS Advances ◽  
2019 ◽  
Vol 4 (61-62) ◽  
pp. 3423-3431
Author(s):  
Daniela K. Calvo-Ramos ◽  
Marina Vega-González ◽  
José Santos-Cruz ◽  
Francisco Javier De Moure-Flores ◽  
Sandra A. Mayén-Hernández
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Nir Spectroscopy ◽  
Improved Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

ABSTRACTNanoparticles of titanium dioxide (TiO2), synthesized by the sonochemical technique, were mixed with different amounts of graphene oxide (GO), obtained by the improved method of Hummer, in order to modify their bandwidth. The TiO2/OG compounds were characterized using different techniques: X-ray Diffraction (XRD), transmission electron microscopy (TEM), Raman and UV-Vis-NIR spectroscopy. TiO2 bandgap decreased, with GO incorporation, from 3.2 to 2.72 eV when GO was present at 20 weigh percentage (TiO2/GO-20%). Photodegradation experiments of methylene blue (MB) were performed with the materials to verify their photocatalytic activity. At 40 minutes, the pure TiO2 degraded 48% of MB, whereas the compound TiO2/GO-20% degraded 88%, showing a good incorporation of both compounds and the improvement of TiO2 photocatalitic properties.

scholarly journals Preparation of Fe3O4/Reduced Graphene Oxide Nanocomposites with Good Dispersibility for Delivery of Paclitaxel

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Xiaojuan Zhang ◽  
Wenbin Cai ◽  
Lingyun Hao ◽  
Suli Feng ◽  
Qing Lin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Targeted Delivery ◽  
Drug Loading ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Vibration Sample Magnetometry ◽  
Mcf 7

The Fe3O4/reduced graphene oxide (Fe3O4/RGO) nanocomposites with good dispersibility were synthesized for targeted delivery of paclitaxel (PTX). Firstly, the superparamagnetic Fe3O4/functional GO nanocomposites were prepared via hydrothermal method in which GO sheets were modified by surfactant wrapping. The Fe3O4/RGO nanocomposites were successively prepared through the reduction of graphene oxide. The products were investigated by Fourier-transform infrared spectrum, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and vibration sample magnetometry. It was found that spherical Fe3O4 nanoparticles were uniformly anchored over the RGO matrix and the nanocomposites were superparamagnetic with saturation magnetization (Ms) of 9.39 emu/g. Then PTX was loaded onto Fe3O4/RGO nanocomposites, and the drug loading capacity was 67.9%. Cell viability experiments performed on MCF-7 demonstrated that the Fe3O4/RGO-loaded PTX (Fe3O4/RGO/PTX) showed cytotoxicity to MCF-7, whereas the Fe3O4/RGO displayed no obvious cytotoxicity. The above results indicated that Fe3O4/RGO/PTX nanocomposites had potential application in tumor-targeted chemotherapy.

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