The Influence of Nitric Acid Treatment on the Crystallographic Structure of Multiwalled Carbon Nanotubes

Commercially available Multiwalled Carbon Nanotubes (MWCNTs) were refluxed with nitric acid in order to improve the density of the acidic surface functional groups. The formation of oxygen containing functional groups may lead to surface enhancement of MWCNTs for further modifications. The crude MWCNTs were refluxed in nitric acid at 100 °C for time ranging between 3 to 24 h. The influence of treatment time on crystalline structure was investigated using X-Ray Diffraction (XRD); the results confirmed that all treated MWCNTs are crystalline. The density of the surface functional groups on treated MWCNTs was examined by Fourier Transform Infrared (FTIR). The FTIR spectrums revealed a strong vibration band at 1739, 1219, 1369 cm-1that indicates covalently bound acidic surface functional groups existed on the treated MWCNTs. The amount of acidic groups increased with the reflux time up to 15 h treatment as measured by an acid-base Boehm titration. The vibrational spectroscopy of these functional groups also increased with the increasing reflux time.

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Features of oxidative functionalization of multiwalled carbon nanotubes

Image Journal of Advanced Materials and Technologies ◽

10.17277/jamt.2021.02.pp.091-100 ◽

2021 ◽

Vol 6 (2) ◽

pp. 091-100

Author(s):

Tatyana P. Dyachkova ◽

Evgeny N. Tugolukov ◽

Elena A. Burakova ◽

Yulian A. Khan ◽

Anastasiya A. Pasko ◽

...

Keyword(s):

Carbon Nanotubes ◽

Nitric Acid ◽

Specific Surface ◽

Multiwalled Carbon Nanotubes ◽

Functional Groups ◽

Time Interval ◽

Multiwalled Carbon ◽

Graphene Layers ◽

Transmission Electron ◽

Initial Stage

The paper studies the oxidation laws of multiwalled carbon nanotubes (MWCNTs) of various types, which differ in geometric parameters (diameter, length, specific surface), using nitric acid. In different experiments, the duration of oxidation, the concentration of nitric acid, and the consumption of HNO3 per 1 g of MWCNTs were varied. The qualitative composition of the formed oxygen-containing functional groups and the changes occurring with the graphene layers of nanotubes were established by the methods of IR and Raman spectroscopy, and transmission electron microscopy. The total oxygen content in the samples was determined by energy dispersive analysis. The degree of MWCNTs functionalization with acidic functional groups was determined by Boehm titration. An X-ray structural analysis of the obtained samples was carried out and their specific surface area was estimated. It was determined that the most serious changes in the functionalization degree occurred during the first 1–3 hours of oxidation. During this time interval, the achieved values of the functionalization degree were determined mainly by the shape of the MWCNTs graphene layers. At 7–10 hours of treatment, regardless of the initial parameters, MWCNTs have the functionalization degree in the range of 0.5–0.7 mmoLg–1. At the initial stage of oxidation, the amorphous phase is removed. Using dilute solutions of nitric acid does not allow obtaining oxidized nanotubes with the high functionalization degree. It is expedient to reduce the consumption of 65 % HNO3 to 40 mL per 1 g of MWCNTs.

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CVD Synthesis, Functionalization and CO2 Adsorption Attributes of Multiwalled Carbon Nanotubes

Processes ◽

10.3390/pr7090634 ◽

2019 ◽

Vol 7 (9) ◽

pp. 634 ◽

Cited By ~ 3

Author(s):

Shazia Shukrullah ◽

Muhammad Yasin Naz ◽

Norani M. Mohamed ◽

Khalid A. Ibrahim ◽

Nasser M. AbdEl-Salam ◽

...

Keyword(s):

Carbon Dioxide ◽

Carbon Nanotubes ◽

Adsorption Capacity ◽

Multiwalled Carbon Nanotubes ◽

Functional Groups ◽

Co2 Adsorption ◽

Breakthrough Curves ◽

Multiwalled Carbon ◽

Amine Functionalized ◽

Co2 Adsorption Capacity

Carbon dioxide is one of the major greenhouse gases and a leading source of global warming. Several adsorbent materials are being tested for removal of carbon dioxide (CO2) from the atmosphere. The use of multiwalled carbon nanotubes (MWCNTs) as a CO2 adsorbent material is a relatively new research avenue. In this study, Fe2O3/Al2O3 composite catalyst was used to synthesize MWCNTs by cracking ethylene gas molecules in a fluidized bed chemical vapor deposition (CVD) chamber. These nanotubes were treated with H2SO4/HNO3 solution and functionalized with 3-aminopropyl-triethoxysilane (APTS). Chemical modification of nanotubes removed the endcaps and introduced some functional groups along the sidewalls at defected sites. The functionalization of nanotubes with amine introduced carboxylic groups on the tube surface. These functional groups significantly enhance the surface wettability, hydrophilicity and CO2 adsorption capacity of MWCNTs. The CO2 adsorption capacity of as-grown and amine-functionalized CNTs was computed by generating their breakthrough curves. BELSORP-mini equipment was used to generate CO2 breakthrough curves. The oxidation and functionalization of MWCNTs revealed significant improvement in their adsorption capacity. The highest CO2 adsorption of 129 cm3/g was achieved with amine-functionalized MWCNTs among all the tested samples.

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Oxidation of multiwalled carbon nanotubes by nitric acid

Carbon ◽

10.1016/j.carbon.2005.06.019 ◽

2005 ◽

Vol 43 (15) ◽

pp. 3124-3131 ◽

Cited By ~ 528

Author(s):

Iosif Daniel Rosca ◽

Fumio Watari ◽

Motohiro Uo ◽

Tsukasa Akasaka

Keyword(s):

Carbon Nanotubes ◽

Nitric Acid ◽

Multiwalled Carbon Nanotubes ◽

Multiwalled Carbon

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Impacts of structure defects and carboxyl and carbonyl functional groups on the work function of multiwalled carbon nanotubes

Carbon ◽

10.1016/j.carbon.2016.12.046 ◽

2017 ◽

Vol 114 ◽

pp. 526-532 ◽

Cited By ~ 15

Author(s):

Bo Gong ◽

Akitoshi Ikematsu ◽

Keiko Waki

Keyword(s):

Carbon Nanotubes ◽

Work Function ◽

Multiwalled Carbon Nanotubes ◽

Functional Groups ◽

Multiwalled Carbon ◽

Structure Defects

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Graphene oxide-multiwalled carbon nanotubes composite as an anode for lithium ion batteries

Materials Science-Poland ◽

10.1515/msp-2016-0093 ◽

2016 ◽

Vol 34 (3) ◽

pp. 481-486 ◽

Cited By ~ 2

Author(s):

Łukasz Majchrzycki ◽

Mariusz Walkowiak ◽

Agnieszka Martyła ◽

Mikhail Y. Yablokov ◽

Marek Nowicki ◽

...

Keyword(s):

Carbon Nanotubes ◽

Graphene Oxide ◽

Lithium Ion Batteries ◽

Reduced Graphene Oxide ◽

Multiwalled Carbon Nanotubes ◽

Functional Groups ◽

Lithium Ion ◽

Lithium Storage ◽

Multiwalled Carbon ◽

Reduced Graphene

AbstractNowadays reduced graphene oxide (rGO) is regarded as a highly interesting material which is appropriate for possible applications in electrochemistry, especially in lithium-ion batteries (LIBs). Several methods were proposed for the preparation of rGO-based electrodes, resulting in high-capacity LIBs anodes. However, the mechanism of lithium storage in rGO and related materials is still not well understood. In this work we focused on the proposed mechanism of favorable bonding sites induced by additional functionalities attached to the graphene planes. This mechanism might increase the capacity of electrodes. In order to verify this hypothesis the composite of non-reduced graphene oxide (GO) with multiwalled carbon nanotubes electrodes was fabricated. Electrochemical properties of GO composite anodes were studied in comparison with similarly prepared electrodes based on rGO. This allowed us to estimate the impact of functional groups on the reversible capacity changes. As a result, it was shown that oxygen containing functional groups of GO do not create, in noticeable way, additional active sites for the electrochemical reactions of lithium storage, contrary to what has been postulated previously.

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Electrochemical Reduction of CO 2 by SnO x Nanosheets Anchored on Multiwalled Carbon Nanotubes with Tunable Functional Groups

ChemSusChem ◽

10.1002/cssc.201802725 ◽

2019 ◽

Vol 12 (7) ◽

pp. 1443-1450 ◽

Cited By ~ 17

Author(s):

Qi Zhang ◽

Yanxing Zhang ◽

Jianfeng Mao ◽

Junyu Liu ◽

Yue Zhou ◽

...

Keyword(s):

Carbon Nanotubes ◽

Electrochemical Reduction ◽

Multiwalled Carbon Nanotubes ◽

Functional Groups ◽

Multiwalled Carbon

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Transformation of singlewalled carbon nanotubes to multiwalled carbon nanotubes and onion-like structures by nitric acid treatment

Synthetic Metals ◽

10.1016/s0379-6779(02)01254-7 ◽

2004 ◽

Vol 140 (1) ◽

pp. 1-8 ◽

Cited By ~ 23

Author(s):

Kay Hyeok An ◽

Kwan Koo Jeon ◽

Jeong-Mi Moon ◽

Sung Jin Eum ◽

Cheol Woong Yang ◽

...

Keyword(s):

Carbon Nanotubes ◽

Nitric Acid ◽

Multiwalled Carbon Nanotubes ◽

Acid Treatment ◽

Multiwalled Carbon

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Enhancement of Gas Sensing Characteristics of Multiwalled Carbon Nanotubes by CF4Plasma Treatment for SF6Decomposition Component Detection

Journal of Nanomaterials ◽

10.1155/2015/171545 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Xiaoxing Zhang ◽

Xiaoqing Wu ◽

Bing Yang ◽

Hanyan Xiao

Keyword(s):

Carbon Nanotubes ◽

Multiwalled Carbon Nanotubes ◽

Recovery Time ◽

Treatment Time ◽

Gas Sensing ◽

Gas Sensitivity ◽

Multiwalled Carbon ◽

State Evaluation ◽

Response And Recovery ◽

Sensing Characteristics

H2S and SO2are important gas components of decomposed SF6of partial discharge generated by insulation defects in gas-insulated switchgear (GIS). Therefore, H2S and SO2detection is important in the state evaluation and fault diagnosis of GIS. In this study, dielectric barrier discharge was used to generate CF4plasma and modify multiwalled carbon nanotubes (MWNTs). The nanotubes were plasma-treated at optimum discharge conditions under different treatment times (0.5, 1, 2, 5, 8, 10, and 12 min). Pristine and treated MWNTs were used as gas sensors to detect H2S and SO2. The effects of treatment time on gas sensitivity were analyzed. Results showed that the sensitivity, response, and recovery time of modified MWNTs to H2S were improved, but the recovery time of SO2was almost unchanged. At 10 min treatment time, the MWNTs showed good stability and reproducibility with better gas sensing properties compared with the other nanotubes.

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