Pseudo-topotactic conversion of carbon nanotubes to T-carbon nanowires under picosecond laser irradiation in methanol

Jinying Zhang,Rui Wang,Wenjun Wang,Xin Li,Xi Zhu,Dan Zhao Dan Zhao,Chenxiao Han,Chuansheng Ma,Haibin Su,Aifei Pan,Chunming Niu

doi:10.1038/s41467-017-00817-9

Jinying Zhang, Rui Wang + Show 9 more

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https://doi.org/10.1038/s41467-017-00817-9

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Abstract

Pseudo-topotactic conversion of carbon nanotubes into one-dimensional carbon nanowires is a challenging but feasible path to obtain desired diameters and morphologies. Here, a previously predicted but experimentally unobserved carbon allotrope, T-carbon, has been produced from pseudo-topotactic conversion of a multi-walled carbon nanotube suspension in methanol by picosecond pulsed-laser irradiation. The as-grown T-carbon nanowires have the same diameter distribution as pristine carbon nanotubes, and have been characterized by high-resolution transmission electron microscopy, fast Fourier transform, electron energy loss, ultraviolet–visible, and photoluminescence spectroscopies to possess a diamond-like lattice, where each carbon is replaced by a carbon tetrahedron, and a lattice constant of 7.80 Å. The change in entropy from carbon nanotubes to T-carbon reveals the phase transformation to be first order in nature. The computed electronic band structures and projected density of states are in good agreement with the optical absorption and photoluminescence spectra of the T-carbon nanowires.

Highlights

Pseudo-topotactic conversion of carbon nanotubes into one-dimensional carbon nanowires is a challenging but feasible path to obtain desired diameters and morphologies
The synthesis of metastable carbon structures became feasible with the emergence of new synthetic technology
The phonon density of states, specific heat, and entropy of graphite, diamond, Carbon nanotubes (CNTs), and T-carbon were calculated with the quasi-harmonic approximation as shown in Supplementary Fig. 9 and Supplementary Table 343

Summary

Introduction

Pseudo-topotactic conversion of carbon nanotubes into one-dimensional carbon nanowires is a challenging but feasible path to obtain desired diameters and morphologies. A previously predicted but experimentally unobserved carbon allotrope, T-carbon, has been produced from pseudo-topotactic conversion of a multi-walled carbon nanotube suspension in methanol by picosecond pulsed-laser irradiation. Diamond particles[27] and C8 like metastable carbon particles[18, 19] have been produced from amorphous carbon by nanosecond pulsed lasers. Different structural forms of carbon were produced by laser irradiation of CNT films under a nitrogen atmosphere[30]. We describe the synthesis and characterization of a previously unobserved carbon allotrope (T-carbon) NW by pseudo-topotactic conversion of multi-walled CNTs (MWCNTs) in methanol solvent by picosecond laser irradiation under a nitrogen atmosphere

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