The doping of carbon nanotubes with nitrogen and their potential applications

Ayala, Paola; Arenal, Raúl; Rümmeli, Mark H.; Rubio, Ángel; Pichler, Thomas

doi:10.1016/j.carbon.2009.10.009

Cited by 541 publications

(411 citation statements)

References 101 publications

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“…These images confirm previous studies suggesting the incorporation of nitrogen atoms in the honeycomb carbon structure of a NT, which usually implies the presence of defects (1)(2)(3). This is corroborated by the higher sensitivity of CN xSWNTs under the electron beam (see Supplementary Movies 1 and 2).…”

supporting

confidence: 90%

“…These findings provide key information for the applications of these nanostructures. Doped carbon nanotubes (NT), notably nitrogen-doped (CN x -NT), have attracted much attention because of their interesting physical and chemical properties (1)(2)(3)(4). Knowledge of the atomic arrangement of the dopant atoms in such nanostructures is essential for a complete understanding of the material's electronic properties, e.g.…”

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Atomic Configuration of Nitrogen-Doped Single-Walled Carbon Nanotubes

et al. 2014

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Abstract:Having access to the chemical environment at the atomic level of a dopant in a nanostructure is crucial for the understanding of its properties. We have performed atomicallyresolved electron energy-loss spectroscopy to detect individual nitrogen dopants in single-walled carbon nanotubes and compared with first principles calculations. We demonstrate that nitrogen doping occurs as single atoms in different bonding configurations: graphitic-like and pyrroliclike substitutional nitrogen neighbouring local lattice distortion such as Stone-Thrower-Wales defects. The stability under the electron beam of these nanotubes has been studied in two extreme cases of nitrogen incorporation content and configuration. These findings provide key information for the applications of these nanostructures. Doped carbon nanotubes (NT), notably nitrogen-doped (CN x -NT), have attracted much attention because of their interesting physical and chemical properties (1)(2)(3)(4). Knowledge of the atomic arrangement of the dopant atoms in such nanostructures is essential for a complete understanding of the material's electronic properties, e.g. field emission (5) or transport (6) properties. This requires precision measurements, combining high spatial resolution and high spectroscopic sensitivity. Several techniques have been deployed with this aim, but until now none of them have provided the required information in such nanostructures. Most characterization techniques, such as Raman spectroscopy and x-ray absorption spectroscopy (XAS), have relatively low spatial resolution, of the order of hundreds of nanometers, and in some cases only provide indirect information (1,2). Thus, local structural and analytical methods are needed. Scanning tunneling microscopy (STM) and spectroscopy (STS) are local techniques for studying the structural and electronic features/properties of materials. Indeed, some studies have been reported on CN x -NT (7-9) and recently also on N-doped graphene (10,11). However, chemical characterization cannot be unambiguously performed from the STM/STS analysis. Indeed, the interpretation of the results remains complicated, as different local structures may give rise to similar features (7-11). In this sense, high-resolution transmission electron microscopy (HRTEM) and scanning TEM (STEM) combined with electron energy-loss spectroscopy (EELS) have provided very valuable and rich information at the atomic scale (12).Great progress has been made in (S)TEM due to the development of aberration-corrected microscopes (12)(13)(14). Recent work has demonstrated that annular dark-field imaging performed in a C s -probe corrected STEM enables quantitative atom-by-atom analysis of 2D low-Z materials such as h-BN (13). Single atoms have also been investigated via STEM-EELS in these materials (12,(14)(15)(16)(17)(18)(19)(20)(21). Three recent works have demonstrated the possibility to identify by STEM-EELS the presence of N atoms in graphene (19)(20)(21). In addition, N atoms have been also detected in Nimplanted multi-walle...

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Atomic Configuration of Nitrogen-Doped Single-Walled Carbon Nanotubes

et al. 2014

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“…41), and on nitrogen-doped nanotubular structures, about which overviews can also be found elsewhere. 42,43 A very recent overview of nitrogen-doped porous carbons has just been presented by Shen and Fan. 44 Nevertheless we would like to introduce some more unconventional routes towards N-doped carbon materials that do not follow the classical pathways.…”

Section: Synthetic Routes Towards N-doped Carbonsmentioning

confidence: 99%

Doping carbons beyond nitrogen: an overview of advanced heteroatom doped carbons with boron, sulphur and phosphorus for energy applications

Paraknowitsch

Thomas

2013

Energy Environ. Sci.

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Heteroatom doped carbon materials represent one of the most prominent families of materials that are used in energy related applications, such as fuel cells, batteries, hydrogen storage or supercapacitors. While doping carbons with nitrogen atoms has experienced great progress throughout the past decades and yielded promising material concepts, also other doping candidates have gained the researchers' interest in the last few years. Boron is already relatively widely studied, and as its electronic situation is contrary to the one of nitrogen, codoping carbons with both heteroatoms can probably create synergistic effects. Sulphur and phosphorus have just recently entered the world of carbon synthesis, but already the first studies published prove their potential, especially as electrocatalysts in the cathodic compartment of fuel cells. Due to their size and their electronegativity being lower than those of carbon, structural distortions and changes of the charge densities are induced in the carbon materials. This article is to give a state of the art update on the most recent developments concerning the advanced heteroatom doping of carbon that goes beyond nitrogen. Doped carbon materials and their applications in energy devices are discussed with respect to their boron-, sulphur-and phosphorus-doping. Broader contextThe research and design of novel materials that are applicable in various energy devices represent one of the central and most thriving subjects within today's scientic work. The challenges do not only rely on the tremendous need to overcome traditional fossil fuel based energy recovery. While a lot of sustainable concepts already exist, these require the development of high performance materials that are able to cope with certain challenges, e.g. the dependence on highly expensive and rather not abundantly available noble metals, and also a lack of long term stability of those. Researchers have been carrying out numerous studies concentrating on nding alternative materials that can be applied in novel energy devices. Those alternative materials should most preferably be free of noble metals, avoid expensive precursor systems, be sustainable and not rely on the fossil energy sources that are to be replaced, and of course exhibit high activity in the devices they are designed for. One class of materials in whose development and understanding researchers have put strong effort is heteroatom-doped carbon materials. By heteroatom doping the properties are altered compared to crude carbon materials. The by far most intensely studied doping candidate is nitrogen, capable of not only increasing electric conductivity, but also the catalytic activity of carbons. Such N-doped carbons have advanced tremendously in the past few years, especially by proving their usefulness as electrocatalysts for the reduction of oxygen in fuel cell cathodes, or as electrode materials in supercapacitors. Meanwhile the spectrum of doping has been widened, and novel doped carbons have been reported, indicating the promising pote...

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“…[4][5][6] The heteroatom doping of nitrogen significantly alters the microstructure, electrical conductivity, chemical reactivity and electrochemical properties of CNTs including their pseudocapacitance, wherein the electrochemical behaviour itself is dependent on the dominant nitrogen moiety. [4][5][6] In general, the additional electrons provided by nitrogen are expected to produce electron donor regions. 6 Pyridinic and pyrrole-like functionalities are considered electroactive due to their electron donor character, whereas nitrogen atoms in imides and lactams have been proposed to be electroactive as well owing to their edge locations and the conjugation within their six-membered rings.…”

Section: Paper: C4cc04876hmentioning

confidence: 99%