Microstructural and electrochemical impedance characterization of bio-functionalized ultrafine ZnS nanocrystals–reduced graphene oxide hybrid for immunosensor applications

Nanoscale ◽  
2013 ◽  
Vol 5 (21) ◽  
pp. 10494 ◽  
Author(s):  
Sujeet K. Mishra ◽  
Avanish K. Srivastava ◽  
Devendra Kumar ◽  
Ashok M. Biradar ◽  
Rajesh
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Electrochemical Impedance ◽  
Reduced Graphene ◽  
Zns Nanocrystals ◽  
Impedance Characterization

scholarly journals Synthesis and Characterization of Magnetic Fe3O4/Reduced Graphene Oxide and its Application in Determination of Dopamine

2019 ◽  
Vol 31 (12) ◽  
pp. 2785-2792 ◽  
Author(s):  
A.R. Rosli ◽  
S.H. Loh ◽  
F. Yusoff
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Electrochemical Impedance ◽  
Reduction Process ◽  
Cubic Phase ◽  
Real Sample Analysis ◽  
Reduced Graphene ◽  
Limit Of Quantitation

An electrochemical sensor to determine dopamine in the human body was fabricated based on modified iron oxide/reduced graphene oxide/glassy carbon electrode (Fe3O4/r-GO/GCE). Determination of dopamine is significance nowadays as the abnormal level may cause various mental health diseases as well as Parkinson’s disease. The Fe3O4/r-GO nanocomposite was synthesized via Hummer’s method with a slight modification and characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Brunauer Emmett-Teller (BET). The presence of Fe3O4 onto the surface of r-GO was confirmed by SEM analysis which shows the bulky porous sponge-like structure attached to an exfoliated sheet of r-GO. FTIR analysis proved the presence of the functional group in existing composites via oxidation process of graphene oxide and reduction process of reduced graphene oxide while the crystalline form of Fe3O4/r-GO was determined using XRD analysis. The diffraction peaks index to the cubic phase was noticeable indicating the successful crystallization of the composites. The catalytic activity of bare GCE and modified GCE (Fe3O4/r-GO/ GCE) were observed using electrochemical characterization of cyclic voltammetry, differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) with optimum pH of 7, a concentration of 100 μM, and the scan rate of 250 mV s-1. The observed DPV response linearly depends on dopamine concentration in the range of 20-100 μM, with correlation coefficients of 0.9876. The detection limit obtained for the real sample analysis was found to be 0.569 μM while the limit of quantitation was 1.897 μM. The percentage of recovery, repeatability and reproducibility was 113, 82.81 and 7.19 %, respectively.

Synthesis and characterization of reduced graphene oxide by cobalt oxide composite electrode

2020 ◽  
Author(s):  
S. Veeresh ◽  
H. Ganesh ◽  
Y. S. Nagaraj ◽  
M. Vandana ◽  
S. P. Ashokkumar ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Cobalt Oxide ◽  
Composite Electrode ◽  
Synthesis And Characterization ◽  
Oxide Composite ◽  
Reduced Graphene

scholarly journals A Facile and Green Synthesis of a MoO2-Reduced Graphene Oxide Aerogel for Energy Storage Devices

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 594 ◽  
Author(s):  
Mara Serrapede ◽  
Marco Fontana ◽  
Arnaud Gigot ◽  
Marco Armandi ◽  
Glenda Biasotto ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Chemical Reduction ◽  
Low Cost ◽  
Xps Analysis ◽  
3D Scaffold ◽  
Energy Storage Devices ◽  
Reduced Graphene

A simple, low cost, and “green” method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO2 aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO2 compound. The pseudocapacitance contribution from the resulting embedded MoO2 microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO2 particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.

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