scholarly journals Synthesis and characterization of LaMnO3 nanocrystals and graphene oxide: fabrication of graphene oxide–LaMnO3 sensor for simultaneous electrochemical determination of hydroquinone and catechol

2019 ◽  
Vol 9 (4) ◽  
pp. 255-267 ◽  
Author(s):  
Sedighe Akbari ◽  
Mohammad Mehdi Foroughi ◽  
Hadi Hassani Nadiki ◽  
Shohreh Jahani
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Simultaneous Determination ◽  
High Surface ◽  
High Surface Area ◽  
Electrochemical Determination ◽  
Great Decrease ◽  
X Ray ◽  
Transmission Electron

For the first time, a new method for preparation of graphene oxide-LaMnO3 (GO-LaMnO3) nanocompositeas a material of electrochemical sensor for simultaneous determination of catechol (CT) and hydroquinone (HQ) is developed. LaMnO3 nanoparticles have been characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX) technique. Due to the excellent catalytic activity, enhanced electrical conductivity and high surface area, the simultaneous determination of HQ and CT with two well-defined peaks has been achieved at the GO-LaMnO3 modified electrode. Comparing with unmodified electrodes, the oxidation currents of HQ and CT increased remarkably. Also, the result exhibited a great decrease in anodic overpotentialresulting in about 150 mV negative shift of potential. The catalytic peak current values are found linearly dependent on the HQ and CT concentrations in the range of 0.5–433.3 and 0.5–460.0 μM with sensitivity of 0.0719 and 0.0712 μA μM-1, respectively. The detection limits for HQ and CT are determined as 0.06 and 0.05 μM, respectively.

Ni-doped, urchin-like Bi2S3 particles for electrocatalytic oxidation of glucose

2021 ◽  
pp. 2150006
Author(s):  
Biao Wang ◽  
Ya Liu ◽  
Xu Huai ◽  
Yuqing Miao
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Electrocatalytic Oxidation ◽  
High Surface ◽  
High Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Capacitance Current ◽  
Oxidation Of Glucose

In order to develop non-noble metal-based electrocatalysts for glucose oxidation, the Ni-doped, urchin-like Bi2S3 particles were prepared by a solvothermal method using the solvent of ethylene glycol/H2O. The obtained products were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The background signal from capacitance current is relatively low and the electrocatalytic oxidation current of glucose relatively high due to the urchin-like nanostructure of Bi2S3 particles and high surface area where the presence of Bi also improves the electrocatalytic performance of NiII/NiIII shift.

scholarly journals Graphene Oxide Nanoribbons in Chitosan for Simultaneous Electrochemical Detection of Guanine, Adenine, Thymine and Cytosine

Biosensors ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 30 ◽  
Author(s):  
Jiayun Zhou ◽  
Shaopei Li ◽  
Meissam Noroozifar ◽  
Kagan Kerman
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Coupling Reaction ◽  
Electrochemical Determination ◽  
Dna Bases ◽  
Graphene Oxide Nanoribbons ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Herein, graphene oxide nanoribbons (GONRs) were obtained from the oxidative unzipping of multi-walled carbon nanotubes. Covalent coupling reaction of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxy succinimide (NHS) with amine functional groups (-NH2) of the chitosan natural polymer (CH) was used for entrapping GONRs on the activated glassy carbon electrode (GCE/GONRs-CH). The nanocomposite was characterized by high-resolution transmission electron microscopy (HRTEM), and field-emission scanning electron microscopy (FESEM). In addition, the modification steps were monitored using FTIR. The nanocomposite-modified electrode was used for the simultaneous electrochemical determination of four DNA bases; guanine (G), adenine (A), thymine (T) and cytosine (C). The nanocomposite-modified GCE displayed a strong, stable and continuous four oxidation peaks during electrochemistry detection at potentials 0.63, 0.89, 1.13 and 1.27 V for G, A, T and C, respectively. The calibration curves were linear up to 256, 172, 855 and 342 μM with detection limits of 0.002, 0.023, 1.330 and 0.641 μM for G, A, T and C, respectively. The analytical performance of the GCE/GONRs-CH has been used for the determination of G, A, T and C in real samples and obtained a recovery percentage from 91.1%–104.7%. Our preliminary results demonstrated that GCE/GONRs-CH provided a promising platform to detect all four DNA bases for future studies on DNA damage and mutations.

SYNTHESIS AND CHARGE–DISCHARGE PROPERTIES OF POROUS CO3O4 NANOROD BUNDLE ELECTRODE

NANO ◽  
2012 ◽  
Vol 07 (05) ◽  
pp. 1250036 ◽  
Author(s):  
FEI TENG ◽  
JUN WANG ◽  
MINDONG CHEN ◽  
DENNIS DESHENG MNEG
Keyword(s):  
Electron Microscopy ◽  
High Surface ◽  
High Surface Area ◽  
Lithium Ion ◽  
Nitrogen Adsorption ◽  
X Ray ◽  
Transmission Electron ◽  
Rate Capacity ◽  
Nanorod Bundle ◽  
Charge Discharge

The Co3O4 nanorod bundles are synthesized by a hydrothermal method. The samples are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED), X-ray powder diffractometer (XRD), and nitrogen adsorption. It is important that the as-obtained Co3O4 nanorod bundles are assembled by nanoparticles. The porous nanorod bundle electrode exhibits a higher rate capacity and a higher reverse capability for lithium ion battery than the solid nanorods, which is attributed to the high surface area and the porous structure.

Characterization of an Inorganic Cryptomelane Nanomaterial Synthesized by a Novel Process Using Transmission Electron Microscopy and X-Ray Diffraction

2008 ◽  
Vol 14 (4) ◽  
pp. 328-334 ◽  
Author(s):  
Longzhou Ma ◽  
Thomas Hartmann ◽  
Marcos A. Cheney ◽  
Nancy R. Birkner ◽  
Pradip K. Bhowmik
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Surface ◽  
High Surface Area ◽  
Rietveld Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Potential Applications ◽  
Diffraction Patterns ◽  
Crystallographic Planes

Layer- and tunnel-structured manganese oxide nanomaterials are important because of their potential applications in industrial catalysis. A novel soft chemistry method was developed for the synthesis of inorganic cryptomelane nanomaterials with high surface area. Bright field transmission electron microscopy (BF-TEM) and high-resolution transmission electron microscopy (HRTEM) techniques were employed to characterize this nanomaterial. A nanosized material with fibrous texture comprised of 140–160 nm striations was identified by BF-TEM imaging. HRTEM images show multiple atomic morphologies such as “helix-type,” “doughnut-like,” and tunnel structures lying on different crystallographic planes. The crystallographic parameters of this material were analyzed and measured by X-ray powder diffraction (XRD) showing that the synthesized nanomaterial is single phased and corresponds to cryptomelane with major diffraction peaks (for 10° < 2θ < 60°) at d-spacing values of 6.99, 4.94, 3.13, 2.40, 2.16, 1.84, 1.65, and 1.54 Å. A “doughnut-like” crystal structure was confirmed based on the crystallographic data. Structure and lattice parameters refinement was performed by XRD/Rietveld analysis. Simple simulation of HRTEM images and selected area diffraction patterns were applied to interpret the HRTEM images as observed.

scholarly journals Pd Nanoparticles Stabilized on the Cross-Linked Melamine-Based SBA-15 as a Catalyst for the Mizoroki–Heck Reaction

2021 ◽  
Author(s):  
Ayat Nuri ◽  
Abolfazl Bezaatpour ◽  
Mandana Amiri ◽  
Nemanja Vucetic ◽  
Jyri-Pekka Mikkola ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Inductively Coupled Plasma ◽  
High Surface ◽  
High Surface Area ◽  
Coupling Reaction ◽  
Pd Nanoparticles ◽  
Significant Activity ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Ft Ir

AbstractMesoporous SBA-15 silicate with a high surface area was prepared by a hydrothermal method, successively modified by organic melamine ligands and then used for deposition of Pd nanoparticles onto it. The synthesized materials were characterized with infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nitrogen physisorption, scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) and inductively coupled plasma (ICP-OES). The catalyst was effectively used in the Mizoroki–Heck coupling reaction of various reactants in the presence of an organic base giving the desired products in a short reaction time and with small catalysts loadings. The reaction parameters such as the base type, amounts of catalyst, solvents, and the temperature were optimized. The catalyst was easily recovered and reused at least seven times without significant activity losses. Graphic Abstract

scholarly journals Attached β-cyclodextrin/γ-(2,3-epoxypropoxy) propyl trimethoxysilane to graphene oxide and its application in copper removal

2017 ◽  
Vol 75 (10) ◽  
pp. 2403-2411 ◽  
Author(s):  
Zongxue Yu ◽  
Qi Chen ◽  
Liang Lv ◽  
Yang Pan ◽  
Guangyong Zeng ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Esterification Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cavity Structure ◽  
Optimum Ph ◽  
Exchange Adsorption ◽  
Langmuir Isotherm Model

The environmental applications of graphene oxide and β-cyclodextrin (β-CD) have attracted great attention since their first discovery. Novel nanocomposites were successfully prepared by using an esterification reaction between β-cyclodextrin/γ-(2,3-epoxypropoxy) propyl trimethoxysilane grafted graphene oxide (β-CD/GPTMS/GO). The β-CD/GPTMS/GO nanocomposites were used to remove the Cu2+ from aqueous solutions. The characteristics of β-CD/GPTMS/GO were detected by scanning electron microscopy (SEM), Fourier transform infrared, X-ray diffraction (XRD), thermogravimetric analysis (TG) and energy dispersive X-ray (EDX). The dispersibility of graphene oxide was excellent due to the addition of β-CD. The adsorption isotherms data obtained at the optimum pH 7 were fitted by Langmuir isotherm model. The excellent adsorption properties of β-CD/GPTMS/GO for Cu2+ ions could be attributed to the apolar cavity structure of β-CD, the high surface area and abundant functional groups on the surface of GO. The adsorption patterns of β-CD/GPTMS/GO were electrostatic attraction, formation of host-guest inclusion complexes and the ion exchange adsorption. The efficient adsorption of β-CD/GPTMS/GO for Cu2+ ions suggested that these novel nanocomposites may be ideal candidates for removing other cation pollutants from waste water.

Three-Dimensional Holey-Graphene Architectures for Highly Sensitive Enzymatic Electrochemical Determination of Hydrogen Peroxide

2019 ◽  
Vol 19 (11) ◽  
pp. 7404-7409 ◽  
Author(s):  
Aihua Jing ◽  
Gaofeng Liang ◽  
Hao Shi ◽  
Yixin Yuan ◽  
Quanxing Zhan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Graphene Oxide ◽  
Three Dimensional ◽  
Electrochemical Determination ◽  
High Specific Surface Area ◽  
3D Graphene ◽  
Practical Applications ◽  
Transmission Electron ◽  
Mild Defect

Three-dimensional (3D) graphene with high specific surface area, excellent conductivity and designed porosity is essential for many practical applications. Herein, holey graphene oxide with nano pores was facilely prepared via a convenient mild defect-etching reaction and then fabricated to 3D nanostructures via a reduction method. Based on the 3D architectures, a novel enzymatic hydrogen peroxide sensor was successfully fabricated. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to characterize the 3D holey graphene oxide architectures (3DHGO). Cyclic voltammetry (CV) was used to evaluate the electrochemical performance of 3DHGO at glassy carbon electrode (GCE). Excellent electrocatalytic activity to the reduction of H2O2 was observed, and a linear range of 5.0×10-8~5.0×10-5 M with a detection limit of 3.8×10-9 M was obtained. These results indicated that 3DHGO have potential as electrochemical biosensors.

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.

A one-step electrochemically reduced graphene oxide based sensor for sensitive voltammetric determination of furfural in milk products

2021 ◽  
Vol 13 (1) ◽  
pp. 56-63
Author(s):  
Qiuqiu Wang ◽  
Juanhua Zhang ◽  
Yanbo Xu ◽  
Yingyi Wang ◽  
Liang Wu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Milk Products ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide ◽  
One Step ◽  
Dairy Milk

One-step electrochemically reduced graphene oxide with high surface area and improved electron transfer kinetics shows great performances in the determination of furfural in dairy milk.

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