Effects of acid treatment duration and sulfuric acid molarity on purification of multi-walled carbon nanotubes

Mortazavi, Seyedeh Zahra; Novinrooz, A. J.; Reyhani, A.; Mirershadi, Soghra

doi:10.2478/s11534-010-0017-9

Cited by 7 publications

(8 citation statements)

References 26 publications

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“…Finally, the average diameter of carbon nanotubes treated with 6M H 2 Cr 2 O 7 was close to each other. The decrease in diameter of CNTs was also reported in [ 44 ] for sulfuric acid treatment.…”

Section: Resultssupporting

confidence: 76%

“…The direct proof of stronger oxidation of samples in 6M H 2 Cr 2 O 7 solutions is the lowest average diameter of CNTs (according to TEM) and graphitization degree Y (according to XRD). Usually, the increase of I(D)/I(G) after acid treatment takes place [ 44 , 53 ] and the cases of its decrease compared to pristine material are rare, but in such papers the initial defectiveness of MWCNTs is low enough (for example, I(D)/I(G) = 0.2 [ 53 ] or I(D)/I(G) = 0.47 [ 44 ]) compared to this paper. The surface area of both types of MWCNTs tends to decrease when exposing dichromium acid solution treatment ( Table 3 ).…”

Section: Resultsmentioning

confidence: 99%

“…When comparing the specific capacitance of MWCNTs treated with sulfuric acid, which is one of the most frequently used oxidizers [ 44 ], it can be concluded that the treatment with dichromic acid leads to higher specific capacitance of material as well as lower C:O ratios [ 2 ]. Moreover, sometimes the oxidative treatment with sulfuric acid or nitric acid does not lead to a significant improvement in specific capacitance (the latter varied from 2.9 to 3.67 F g −1 for chemically treated CNT-based textile samples) [ 31 ].…”

Section: Resultsmentioning

confidence: 99%

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Treatment of Multi-Walled Carbon Nanotubes with Dichromic Acid: Oxidation and Appearance of Intercalation

et al. 2023

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This work is dedicated to the study of the treatment of multi-walled carbon nanotubes (MWCNTs) with dichromic acid. The dichromic acid was formed by dissolving different concentrations of CrO3 in water. The effect of the concentration of dichromic acid on the change in texture characteristics, elemental composition, defectiveness, graphitization degree, and surface chemistry of MWCNTs was investigated using various analytical techniques, such as transmission electron microscopy, energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, and X-ray photoelectron spectroscopy (XPS). Testing of MWCNTs as electrodes for supercapacitors in 3.5 M H2SO4 solution was carried out using cyclic voltammetry. A decrease in the average diameter of CNTs after treatment was found. The EDX and XPS showed that the oxygen content on the surface of MWCNTs increased after treatment with dichromic acid. The formation of Cr2O3 after treatment with dichromic acid was detected by XPS. High angle annular dark field scanning transmission electron microscopy was used to confirm the intercalation of the chromium-containing compound between graphene layers of MWCNTs after treatment with dichromic acid. It was found that two different types of MWCNTs showed diverse behavior after treatment. The highest specific capacitance of the MWCNTs after treatment was 141 F g−1 (at 2 mV s−1) compared to 0.3 F g−1 for the untreated sample.

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Section: Resultssupporting

confidence: 76%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Treatment of Multi-Walled Carbon Nanotubes with Dichromic Acid: Oxidation and Appearance of Intercalation

et al. 2023

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“…In addition, the surface of CNT bundles is rather rough and surrounded by a matrix of disordered carbonaceous film (CCFs) embedding the CNTs as a result of the strong acidic attack of the dwCNTs and diaphanous carbon. These CCFs, usually regarded as an unwanted impurity for CNTs, may be removed by further washing with a solution of NaOH. , However, for the purpose of this study, we have chosen to keep the CCFs since these oxidized species may advantageously play the role of anchoring sites for metalorganic copper precursors.…”

Section: Resultsmentioning

confidence: 99%

“…These CCFs, usually regarded as an unwanted impurity for CNTs, may be removed by further washing with a solution of NaOH. 27,31 However, for the purpose of this study, we have chosen to keep the CCFs since these oxidized species may advantageously play the role of anchoring sites for metalorganic copper precursors.…”

Section: ■ Introductionmentioning

confidence: 99%

Grafting Copper Atoms and Nanoparticles on Double-Walled Carbon Nanotubes: Application to Catalytic Synthesis of Propargylamine

et al. 2022

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The decoration of carbon nanotubes (CNTs) by metal nanoparticles (NPs) combines the advantages of a high specific surface material with catalytic properties of metal nanocrystals. Little work has been devoted to the decoration of CNTs with copper NPs, and no evidence of copper atomic decoration of CNTs has shown up until now. Herein, we demonstrate that the strong acidic oxidation of double-walled CNTs (dwCNTs) is very efficient for the decoration of the carbon surface by copper NPs and atoms. This treatment severely degraded the CNT walls and generated a large amount of disordered sp 3 carbon. This amorphous carbon film bears many chemically active functions like carboxyl and hydroxyl ones. In such conditions, the CNT walls behave as very efficient ligands for the stabilization of copper obtained by the thermolysis of the mesityl precursor in organic solution under mild dihydrogen pressure. In addition to copper NPs, we evidenced the presence of a regular coverage with copper atoms over the dwCNTs. This nanocomposite catalyzes the quantitative synthesis of propargylamines via one A 3 -type coupling reaction. Five consecutive catalytic cycles with 100% yield could be performed with no loss of activity, and the combination of Cu supported on dwCNTs allows a facile recycling of the catalytic material.

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Polydopamine‐modified MWCNTs‐glassy Carbon Electrode, a Selective Electrochemical Morphine Sensor

2021

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An electrochemical sensor based on a glassy carbon electrode was prepared using f‐MWCNTs and polydopamine. Several techniques were used to investigate the surface features. Voltammetric techniques were used to evaluate the electrocatalyst efficiency, and it was used for morphine determination using differential pulse voltammetry. Different parameters affecting the method‘s sensitivity and selectivity were optimized. The linear dynamic range was 0.075–75.0 μM with a detection limit of 0.06 μM morphine. Also, the method‘s selectivity was tested, which was proved to be satisfactory. Finally, the sensor was successfully used for morphine determination in human plasma and urine samples with acceptable results.

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Effects of acid treatment duration and sulfuric acid molarity on purification of multi-walled carbon nanotubes

Cited by 7 publications

References 26 publications

Treatment of Multi-Walled Carbon Nanotubes with Dichromic Acid: Oxidation and Appearance of Intercalation

Treatment of Multi-Walled Carbon Nanotubes with Dichromic Acid: Oxidation and Appearance of Intercalation

Grafting Copper Atoms and Nanoparticles on Double-Walled Carbon Nanotubes: Application to Catalytic Synthesis of Propargylamine

Polydopamine‐modified MWCNTs‐glassy Carbon Electrode, a Selective Electrochemical Morphine Sensor

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