scholarly journals Peroxide Electrochemical Sensor and Biosensor Based on Nanocomposite of TiO2 Nanoparticle/Multi-Walled Carbon Nanotube Modified Glassy Carbon Electrode

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 64 ◽  
Author(s):  
L. Andrés Guerrero ◽  
Lenys Fernández ◽  
Gema González ◽  
Marjorie Montero-Jiménez ◽  
Rafael Uribe ◽  
...  
Keyword(s):  
Modified Electrode ◽  
Glassy Carbon ◽  
Sodium Dodecylsulfate ◽  
Modified Electrodes ◽  
Dimethyl Formamide ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Before And After ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

A hydrogen peroxide (H2O2) sensor and biosensor based on modified multi-walled carbon nanotubes (CNTs) with titanium dioxide (TiO2) nanostructures was designed and evaluated. The construction of the sensor was performed using a glassy carbon (GC) modified electrode with a TiO2–CNT film and Prussian blue (PB) as an electrocalatyzer. The same sensor was also employed as the basis for H2O2 biosensor construction through further modification with horseradish peroxidase (HRP) immobilized at the TiO2–fCNT film. Functionalized CNTs (fCNTs) and modified TiO2–fCNTs were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-Ray DifFraction (XRD), confirming the presence of anatase over the fCNTs. Depending on the surface charge, a solvent which optimizes the CNT dispersion was selected: dimethyl formamide (DMF) for fCNTs and sodium dodecylsulfate (SDS) for TiO2–fCNTs. Calculated values for the electron transfer rate constant (ks) were 0.027 s−1 at the PB–fCNT/GC modified electrode and 4.7 × 10−4 s−1 at the PB–TiO2/fCNT/GC electrode, suggesting that, at the PB–TiO2/fCNT/GC modified electrode, the electronic transfer was improved. According to these results, the PB–fCNT/GC electrode exhibited better Detection Limit (LD) and Quantification Limit (LQ) than the PB–TiO2/fCNT/GC electrode for H2O2. However, the PB film was very unstable at the potentials used. Therefore, the PB–TiO2/fCNT/GC modified electrode was considered the best for H2O2 detection in terms of operability. Cyclic Voltammetry (CV) behaviors of the HRP–TiO2/fCNT/GC modified electrodes before and after the chronoamperometric test for H2O2, suggest the high stability of the enzymatic electrode. In comparison with other HRP/fCNT-based electrochemical biosensors previously described in the literature, the HRP–fCNTs/GC modified electrode did not show an electroanalytical response toward H2O2.

scholarly journals Electrochemical Glucose Oxidation Using Glassy Carbon Electrodes Modified with Au-Ag Nanoparticles: Influence of Ag Content

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Nancy Gabriela García-Morales ◽  
Luis Alfonso García-Cerda ◽  
Bertha Alicia Puente-Urbina ◽  
Leonor María Blanco-Jerez ◽  
René Antaño-López ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Electrode Surface ◽  
Glucose Oxidation ◽  
Modified Electrodes ◽  
Alkaline Media ◽  
Carbon Electrodes ◽  
X Ray Diffraction ◽  
Simple Method ◽  
Glassy Carbon Electrodes ◽  
Transmission Electron

This paper describes the application of glassy carbon modified electrodes bearing Aux-Agynanoparticles to catalyze the electrochemical oxidation of glucose. In particular, the paper shows the influence of the Ag content on this oxidation process. A simple method was applied to prepare the nanoparticles, which were characterized by transmission electron microscopy, Ultraviolet-Visible spectroscopy, X-ray diffraction spectroscopy, and cyclic voltammetry. These nanoparticles were used to modify glassy carbon electrodes. The effectiveness of these electrodes for electrochemical glucose oxidation was evaluated. The modified glassy carbon electrodes are highly sensitive to glucose oxidation in alkaline media, which could be attributed to the presence of Aux-Agynanoparticles on the electrode surface. The voltammetric results suggest that the glucose oxidation speed is controlled by the glucose diffusion to the electrode surface. These results also show that the catalytic activity of the electrodes depends on the Ag content of the nanoparticles. Best results were obtained for the Au80-Ag20nanoparticles modified electrode. This electrode could be used for Gluconic acid (GA) production.

scholarly journals Optimization of sulfate removal from wastewater using magnetic multi-walled carbon nanotubes by response surface methodology

2017 ◽  
Vol 76 (10) ◽  
pp. 2593-2602 ◽  
Author(s):  
Vahid Alimohammadi ◽  
Mehdi Sedighi ◽  
Ehsan Jabbari
Keyword(s):  
Carbon Nanotubes ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Polynomial Equation ◽  
X Ray Diffraction ◽  
Adsorption Models ◽  
Sulfate Removal ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Abstract This paper reports a facile method for removal of sulfate from wastewater by magnetic multi-walled carbon nanotubes (MMWCNTs). Multi-walled carbon nanotubes and MMWCNTs were characterized by X-ray diffraction, Raman, transmission electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. The results of the analysis indicated that MMWCNTs were synthesized successfully. The MMWCNTs can be easily manipulated in a magnetic field for the desired separation, leading to the removal of sulfate from wastewater. Response surface methodology (RSM) coupled with central composite design was applied to evaluate the effects of D/C (adsorbent dosage per initial concentration of pollutant (mgadsorbent/(mg/l)initial)) and pH on sulfate removal (%). Using RSM methodology, a quadratic polynomial equation was obtained, for removal of sulfate, by multiple regression analysis. The optimum combination for maximum sulfate removal of 93.28% was pH = 5.96 and D/C = 24.35. The experimental data were evaluated by the Langmuir and Freundlich adsorption models. The adsorption capacity of sulfate in the studied concentration range was 56.94 (mg/g). It was found out that the MMWCNTs could be considered as a promising adsorbent for the removal of sulfate from wastewater.

Electrochemical Determination of Rivastigmine Hydrogen Tartrate at β-Cyclodextrin/Multi-Walled Carbon Nanotubes Modified Electrode

2019 ◽  
Vol 15 (3) ◽  
pp. 211-216
Author(s):  
Bugçe Kılıçyaldır ◽  
Asiye Aslıhan Avan ◽  
Kubilay Güçlü ◽  
Mustafa Özyürek ◽  
Hayati Filik
Keyword(s):  
Carbon Nanotubes ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Pharmaceutical Formulations ◽  
Carbon Electrode ◽  
Good Sensitivity ◽  
Modified Glassy Carbon Electrode ◽  
Chemically Modified ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Background: Electrochemical techniques can easily be adopted to solve many problems of pharmaceutical interest. The implementation of electroanalytical methods in the assay of pharmaceutical formulations has increased greatly. Nowadays, owing to the critical importance of electron transfer and surface properties, chemically modified electrodes have been employed in electrochemical sensors. The chemically modified electrode is one of the most popular electroanalytical sensors and used in several applications. Methods: In this work, a β-cyclodextrine/multi-walled carbon nanotubes (β-CD/MWCNTs) composite modified glassy carbon electrode (GCE) was produced and applied to the detection of Rivastigmine hydrogen tartrate (RVT) in pharmaceutical formulations. The voltammetric feature of RVT at this β- CD/MWCNTs modified electrode was evaluated using cyclic voltammetry and square wave voltammetry. Results: The β-cyclodextrin and multi-walled carbon nanotubes modified glassy carbon electrode displayed good electrocatalytic activity in the oxidation of rivastigmine hydrogen tartrate with relatively high sensitivity, stability and lifetime. The calibration graph of the analyte was linear over the range 10- 1500 µM with two linear segments and the detection limit was obtained as 2.0 µM (S/N=3). The results showed that the electrochemical sensor has good sensitivity and selectivity. Conclusion: The β-CD/MWCNTs modified electrode displayed a high electrochemical activity and good sensitivity toward the oxidation of RVT. Compared with the bare MWCNTs coated sensor, the response of analyte increased soundly and the response potential of target analyte shifted negatively. The results indicated that the β-CD/MWCNTs film coated electrode had good catalysis to the voltammetric oxidation of RVT. The prepared sensor was applied to determine RVT in pharmaceutical samples with satisfactory yields. The outcomes indicate that β-CD/MWCNTs coated electrode is a safe choice for the detection of RVT.

scholarly journals Novel ternary nanocomposites of MWCNTs/PANI/MoS 2 : preparation, characterization and enhanced electrochemical capacitance

2018 ◽  
Vol 5 (1) ◽  
pp. 171365 ◽  
Author(s):  
Ranran Zhang ◽  
Yu Liao ◽  
Shuangli Ye ◽  
Ziqiang Zhu ◽  
Jun Qian
Keyword(s):  
Rate Capability ◽  
Cyclic Voltammogram ◽  
X Ray Diffraction ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Good Rate Capability ◽  
A Current

In this work, nanoflower-like MoS 2 grown on the surface of multi-walled carbon nanotubes (MWCNTs)/polyaniline (PANI) nano-stem is synthesized via a facile in situ polymerization and hydrothermal method. Such a novel hierarchical structure commendably promotes the contact of PANI and electrolyte for faradaic energy storage. In the meanwhile, the double-layer capacitance of MoS 2 is effectively used. The morphology and chemical composition of the as-prepared samples are characterized by scanning and transmission electron microscopies, X-ray diffraction and Fourier transform infrared spectra. The electrochemical performance of the samples is evaluated by cyclic voltammogram and galvanostatic charge–discharge measurements. It is found that the specific capacitance of the obtained MWCNTs/PANI/MoS 2 hybrid is 542.56 F g −1 at a current density of 0.5 A g −1 . Furthermore, the MWCNTs/PANI/MoS 2 hybrid also exhibits good rate capability (62.5% capacity retention at 10 A g −1 ) and excellent cycling stability (73.71% capacitance retention) over 3000 cycles.

Microstructural of Cr/MWCNT Composites and its Catalysis in Synthesis of Biodiesel

2012 ◽  
Vol 455-456 ◽  
pp. 1053-1059
Author(s):  
Xue Hai Fan ◽  
Guo Min Xiao
Keyword(s):  
Electron Microscopy ◽  
Potassium Dichromate ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Ft Ir ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotubes (MWCNTs), potassium dichromate (K2Cr2O7) and sulphuric acid were used for the preparation of Cr/MWCNT composite by impregnation method. The composites were comprehensively characterized by transmission electron microscopy （TEM），energy dispersive X-ray analysis (EDX), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermal gravity analysis (TGA). Due to its unique electrical and structural properties, this composite was applied to the synthesis of biodiesel (FAME) as a catalyst, showing effectively catalytic performance.

Carbon nanotubes and carbon fibers in a flash: an easy and convenient preparation of carbon nanostructures using a conventional microwave

2020 ◽  
Vol 98 (1) ◽  
pp. 49-55 ◽  
Author(s):  
María Fernanda Veloz-Castillo ◽  
Antonio Paredes-Arroyo ◽  
Gerardo Vallejo-Espinosa ◽  
José Francisco Delgado-Jiménez ◽  
Jeffery L. Coffer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Carbon Fibers ◽  
Carbon Nanostructures ◽  
Glass Tube ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Application Fields ◽  
Walled Carbon Nanotubes

The growing interest in nanomaterials in different application fields calls for the implementation of simple, economically appealing, and efficient preparative methods. Among the wide variety of nanomaterials, carbon nanostructures have a special place due to their potential technological applications. Here, we present a fast, cheap, and easy-to-implement microwave-assisted method for the preparation of carbon nanotubes (CNTs) and carbon fibers (CFs) at room pressure conditions. The synthesis involves heating a mixture of graphite and ferrocene contained in a simple glass tube using a conventional microwave oven. A mixture of multi-walled carbon nanotubes (MWCNTs) and Fe3O4 magnetic nanoparticles were obtained quickly (less than 30 s) and in good yields. The products were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), and Raman spectroscopy.

Functionalization of Multi-Walled Carbon Nanotubes Using Microwave Method

2021 ◽  
Vol 1039 ◽  
pp. 237-244
Author(s):  
Firas K. Mohamad Alosfur ◽  
Noor J. Ridha ◽  
Mohammad Hafizuddin Haji Jumali ◽  
S. Radiman ◽  
Khawla J. Tahir ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Surface Area ◽  
Structural Integrity ◽  
Area Measurement ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
Before And After ◽  
Multi Walled Carbon Nanotubes ◽  
Dispersion Test ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotubes (MWCNTs) probably hold with each other and agglomerated due to van der Waals force. Functionalized process was used to reduce its ability to agglomerate and to increase dispersion in solution. The present work is focused on the microwave irradiation in order to achieve rapid functionalization of MWCNTs compared with other known techniques. The power of microwave radiation was selected by investigating the structural integrity of the samples by X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FE-SEM), while BET surface area measurement was used to measure the MWCNT surface area before and after treatment. The dispersion test in the solution was performed to determine the separation capability of untreated MWCNTs and f-MWCNTs.

SYNTHESIS AND CONTROL SIZE OF SnS2 NANOPARTICLES ON THE SURFACE MULTI-WALLED CARBON NANOTUBES

NANO ◽  
2010 ◽  
Vol 05 (03) ◽  
pp. 139-142 ◽  
Author(s):  
ROSTAM MORADIAN ◽  
BANDAR ASTINCHAP
Keyword(s):  
Carbon Nanotubes ◽  
Reaction Temperature ◽  
Acid Mixture ◽  
X Ray Diffraction ◽  
Ultrasound Waves ◽  
Tin Disulfide ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
And Control ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotubes have been decorated by SnS2 nanoparticles with different sizes using a simple chemical method. In this work, first multi-walled carbon nanotubes (MWCNTs) functionalized by using acid mixture, then this system coated by tin disulfide ( SnS2 ) nanoparticles with nanoparticle sizes controlling. The samples have been characterized by X-Ray diffraction and transmission electron microscopy (TEM). We found size and uniformity of the SnS2 nanoparticles influenced by increasing reaction temperature and time. By increasing reaction temperature and time, size of the SnS2 nanoparticles became larger and nonuniform. Also we found that ultrasound waves could be used instead of organic compounds for avoiding agglomeration of the SnS2 nanoparticles on the surface of MWCNTs.

scholarly journals Electrochemical behavior of dye-linked L-proline dehydrogenase on glassy carbon electrodes modified by multi-walled carbon nanotubes

2010 ◽  
Vol 1 ◽  
pp. 135-141 ◽  
Author(s):  
Haitao Zheng ◽  
Leyi Lin ◽  
Yosuke Okezaki ◽  
Ryushi Kawakami ◽  
Haruhiko Sakuraba ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Active Site ◽  
Physical Adsorption ◽  
Carbon Electrodes ◽  
Proline Dehydrogenase ◽  
Glassy Carbon Electrodes ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

A glassy carbon electrode (GC) was modified by multi-walled carbon nanotubes (MWCNTs). The modified electrode showed a pair of redox peaks that resulted from the oxygen-containing functional groups on the nanotube surface. A recombinant thermostable dye-linked L-proline dehydrogenase (L-proDH) from hyperthermophilic archaeon (Thermococcus profundus) was further immobilized by physical adsorption. The modified electrode (GC/MWCNTs/L-proDH) exhibited an electrocatalytic signal for L-proline compared to bare GC, GC/L-proDH and GC/MWCNTs electrodes, which suggested that the presence of MWCNTs efficiently enhances electron transfer between the active site of enzyme and electrode surface. The immobilized L-proDH showed a typical Michaelis–Menten catalytic response with lower apparent constant.

Preparation and Luminescence Property of Multi-Walled Carbon Nanotubes/Europium Doped Yttria Oxide Hybrids

2012 ◽  
Vol 535-537 ◽  
pp. 305-309
Author(s):  
T.G. Liu ◽  
C.S. Chen ◽  
X.D. Xie ◽  
C.Y. Qiu
Keyword(s):  
Carbon Nanotubes ◽  
Electron Microscope ◽  
Optical Property ◽  
Luminescence Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In order to improve their optical property, multi-walled carbon nanotubes (MWNTs) were decorated with europium doped yttria oxide (Y2O3:Eu3+) nanoparticles by co-deposition method, and the products were examined by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and luminescence spectroscopy. Experimental results illuminate that MWNTs can be decorated by the Y2O3:Eu3+ nanoparticles at annealed temperature of 600 and 750°C, respectively. The optical property of MWNTs/Y2O3:Eu3+ nanohybrids shows the most excellent when the MWNTs concentratin is 0.5 wt.% and the molar ratios of Eu to Y is 5:95.

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