From isotope labeled CH3CN to N2inside single-walled carbon nanotubes

Christian Kramberger,Shigeo Maruyama,Takayuki Muro,Toyohiko Kinoshita,Akito Takashima,Erik Einarsson,Theerapol Thurakitseree

doi:10.1039/c3nr04729f

Christian Kramberger, Shigeo Maruyama + Show 5 more

Open Access

https://doi.org/10.1039/c3nr04729f

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Abstract

The observation of one-dimensional N₂ inside single-walled carbon nanotubes raises the questions, how are the N₂ molecules formed and how do they manage to make their way to this peculiar place? We have used N(15) and C(13) isotope labeled acetonitrile during the synthesis of single-walled carbon nanotubes to investigate this process. The isotope shifts of phonons and vibrons are observed by Raman spectroscopy and X-ray absorption. We identify the catalytic decomposition of acetonitrile as the initial step in the reaction pathway to single-walled carbon nanotubes containing encapsulated N₂.

Highlights

The ability of multi-walled carbon nanotubes (MWNTs) to encapsulate N2 was rst demonstrated in ref
If N2 is enclosed in the as-synthesized MWNTs, the nanotubes exhibit a compartmentalized bamboo structure that traps pockets of N2.2,3 The detailed distribution of encapsulated N2 and N incorporated into the walls of MWNTs has been directly imaged by polarized scanning transmission X-ray microscopy.[4]
In MWNTs this is seen as a topological curvature resulting in the formation of separate compartments

Summary

Introduction

1. If N2 is enclosed in the as-synthesized MWNTs, the nanotubes exhibit a compartmentalized bamboo structure that traps pockets of N2.2,3 The detailed distribution of encapsulated N2 and N incorporated into the walls of MWNTs has been directly imaged by polarized scanning transmission X-ray microscopy.[4] The alignment of N2 in the con ning walls has been observed by X-ray absorption.[5,6] A commonly observed effect of using N-containing precursors in the growth of single-walled (SW) and MWNTs by chemical vapor deposition (CVD) is the increased curvature in the emerging sp[2] networks. In MWNTs this is seen as a topological curvature resulting in the formation of separate compartments. In SWNTs, reducing diameters increase the geometrical curvature.[7,8,9,10,11]

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