Infrared Spectral Evidence for the Etching of Carbon Nanotubes:  Ozone Oxidation at 298 K

Mawhinney, Douglas B.; Naumenko, V. M.; Kuznetsova, and Anya; Yates, John T.; and, Jeffrey L. Bahr; Smalley, R. E.

doi:10.1021/ja994094s

Cited by 592 publications

(505 citation statements)

References 17 publications

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“…34 As observed in this study, O 3 oxidation of particle-phase amines, which formed through heterogeneous uptake by ammonium, can also take place when exposed to O 3 . H C H O , H C O O H , C H 3 N O 2 , CH 3 N  C H 2 a n d (CH 3 ) 2 NCHO were confirmed as the major products by both FTIR and PTR-MS. Heterogeneous oxidation usually leads to increases in oxygen-containing species, 69,70 O/C ratio 71 and structure modifications of aerosol particles, 72 subsequently, may alter its hygroscopicity 73 and optical properties. 74 Although most of these products are volatile from ozone oxidation of particulate TMA, a portion of these compounds are in the particle phase.…”

Section: ■ Atmospheric Implicationsmentioning

confidence: 99%

Ozonolysis of Trimethylamine Exchanged with Typical Ammonium Salts in the Particle Phase

Chu

et al. 2016

Environ. Sci. Technol.

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Alkylamines contribute to both new particle formation and brown carbon. The toxicity of particle-phase amines is of great concern in the atmospheric chemistry community. Degradation of particulate amines may lead to secondary products in the particle phase, which are associated with changes in the adverse health impacts of aerosols. In this study, O 3 oxidation of particulate trimethylamine (TMA) formed via heterogeneous uptake of TMA by (NH 4 ) 2 SO 4 , NH 4 HSO 4 , NH 4 NO 3 and NH 4 Cl, was investigated with in situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and proton transfer reaction mass spectrometry (PTR-MS). HCOOH, HCHO, CH 3 NCH 2 , (CH 3 ) 2 NCHO, CH 3 NO 2 , CH 3 N(OH)CHO, CH 3 NHOH and H 2 O were identified as products on all the substrates based upon IR (one-dimensional IR and two-dimensional correlation infrared spectroscopy), quantum chemical calculation and PTR-MS results. A reaction mechanism was proposed to explain the observed products. This work demonstrates that oxidation might be a degradation pathway of particulate amines in the atmosphere. This will aid in understanding the fate of particulate amines formed by nucleation and heterogeneous uptake and their potential health impacts during atmospheric aging.

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Section: ■ Atmospheric Implicationsmentioning

confidence: 99%

Ozonolysis of Trimethylamine Exchanged with Typical Ammonium Salts in the Particle Phase

Chu

et al. 2016

Environ. Sci. Technol.

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“…IR measurements (and associated peak assignments) of functionalised nanotubes have been reported previously. 51,52 Of particular relevance is the peak at 1708 cm À1 (attributed to n(CQO) in the functionalised nanotubes) and the peak at 1647 cm À1 (attributed to quinone type units along the side walls of the nanotubes). 51,52 The peak due to n(CQO) in the carboxylic acid groups is observed at 1720 cm À1 for unattached nanotubes.…”

Section: Infrared Spectroscopymentioning

confidence: 99%

Direct attachment of well-aligned single-walled carbon nanotube architectures to silicon (100) surfaces: a simple approach for device assembly

Shapter

Quinton

et al. 2007

Phys. Chem. Chem. Phys.

115

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A new approach for the attachment of vertically-aligned shortened carbon nanotube architectures to a silicon (100) substrate by chemical anchoring directly to the surface has been demonstrated for the first time. The ordered assembly of single-walled carbon nanotubes (SWCNTs) was accomplished by hydroxylating the silicon surface followed by a condensation reaction with carboxylic acid functionalised SWCNTs. This new nanostructure has been characterised by X-ray photoelectron, Raman and Fourier transform infrared (FTIR) spectroscopy as well as scanning electron and atomic force microscopy. The assembly behaviour of SWCNTs onto the silicon surface shows a fast initial step producing isolated functionalised carbon nanotubes or nanotube bundles anchored to the silicon surface followed by a slower step where the adsorbed nanotubes grow into larger aggregates via van der Waals interactions between adsorbed and solvated nanotubes. The electrochemical and optical properties of the SWCNTs directly attached to silicon have also been investigated. These new nanostructures are excellent electrochemical electrodes. They also fluoresce in the wavelength range 650-800 nm. The successful attachment of the SWCNTs directly to silicon provides a simple, new avenue for fabrication and development of silicon-based nanoelectronic, nano-optoelectronic and sensing devices. Compared to existing techniques, this new approach has several advantages including low operating temperature, low cost and the possibility of further modification.

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“…UV radiation, generated by a high intensity mercury vapor lamp at 185 nm and 254 nm, breaks the molecular bonds on the outer wall of CNT allowing ozone, converted simultaneously from air by UV radiation, to oxidize their surface. 26,27 The oxidation process stops once the CNT surfaces are fully functionalized, preventing the CNT to be completely oxidized into CO and CO 2 molecules.…”

Section: Discussionmentioning

confidence: 99%

“…[26][27][28][29][30][31] However, none of these published methods have been previously performed on CNT arrays. Although the oxidation method described herein is similar to these published methods, it is optimized for CNT arrays, not CNT powders.…”

Section: Discussionmentioning

confidence: 99%

Dry Oxidation and Vacuum Annealing Treatments for Tuning the Wetting Properties of Carbon Nanotube Arrays

Aria

Gharib

2013

JoVE

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In this article, we describe a simple method to reversibly tune the wetting properties of vertically aligned carbon nanotube (CNT) arrays. Here, CNT arrays are defined as densely packed multi-walled carbon nanotubes oriented perpendicular to the growth substrate as a result of a growth process by the standard thermal chemical vapor deposition (CVD) technique.1,2 These CNT arrays are then exposed to vacuum annealing treatment to make them more hydrophobic or to dry oxidation treatment to render them more hydrophilic. The hydrophobic CNT arrays can be turned hydrophilic by exposing them to dry oxidation treatment, while the hydrophilic CNT arrays can be turned hydrophobic by exposing them to vacuum annealing treatment. Using a combination of both treatments, CNT arrays can be repeatedly switched between hydrophilic and hydrophobic.2 Therefore, such combination show a very high potential in many industrial and consumer applications, including drug delivery system and high power density supercapacitors. 3-5The key to vary the wettability of CNT arrays is to control the surface concentration of oxygen adsorbates. Basically oxygen adsorbates can be introduced by exposing the CNT arrays to any oxidation treatment. Here we use dry oxidation treatments, such as oxygen plasma and UV/ozone, to functionalize the surface of CNT with oxygenated functional groups. These oxygenated functional groups allow hydrogen bond between the surface of CNT and water molecules to form, rendering the CNT hydrophilic. To turn them hydrophobic, adsorbed oxygen must be removed from the surface of CNT. Here we employ vacuum annealing treatment to induce oxygen desorption process. CNT arrays with extremely low surface concentration of oxygen adsorbates exhibit a superhydrophobic behavior. Video LinkThe video component of this article can be found at

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Infrared Spectral Evidence for the Etching of Carbon Nanotubes: Ozone Oxidation at 298 K

Cited by 592 publications

References 17 publications

Ozonolysis of Trimethylamine Exchanged with Typical Ammonium Salts in the Particle Phase

Ozonolysis of Trimethylamine Exchanged with Typical Ammonium Salts in the Particle Phase

Direct attachment of well-aligned single-walled carbon nanotube architectures to silicon (100) surfaces: a simple approach for device assembly

Dry Oxidation and Vacuum Annealing Treatments for Tuning the Wetting Properties of Carbon Nanotube Arrays

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