Research ArticleMATERIALS SCIENCE

Growth kinetics of single-walled carbon nanotubes with a (2n, n) chirality selection

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Science Advances  13 Dec 2019:
Vol. 5, no. 12, eaav9668
DOI: 10.1126/sciadv.aav9668
  • Fig. 1 SWCNT growth mode without enough etching agents.

    (A) Growth model for SWCNT growth in the absence of sufficient etching agents. (B) In the growth regime, the SWCNT growth rate (RT), active sites for carbon incorporation (NACT), and catalyst surface carbon concentration (c) plots against the tube chiral angle. (C) Carbon concentration as a function of the SWCNT chiral angle at different fluxes of carbon deposition. The threshold carbon concentration (cth) for catalyst encapsulation is indicated by the red line. (D) The chirality-selective growth of SWCNTs as a function of cmin/cth, where the dark zone indicates the SWCNTs can survive under different carbon fluxes.

  • Fig. 2 SWCNT growth rate.

    (A) Snapshot of a SWCNT (named #1 in our samples) and its magnified image (inset) taken during its growth. (B) Six ETEM images (extracted from movie S1) of the tube taken at different times during growth. (C) SWCNT length plotted as a function of growth time shows a constant growth rate. (D) SWCNT growth rate plots as a function of active catalyst surface area–to–tube diameter ratio.

  • Fig. 3 Raman spectra of carbon nanotubes grown on Co nanoparticles with different CO flow fluxes.

    (A and B) Thirty standard cubic centimeters per minute (sccm), (C and D) 40 sccm, and (E and F) 50 sccm. The excitation laser wavelengths are all labeled. a.u., arbitrary units.

  • Fig. 4 SWCNT chirality selectivity as a function of CO flow rate.

    (A) Chiral angle distributions of SWCNTs grown on quartz-supported Co nanoparticles with different flow rates of CO at 650°C. Chirality map of SWCNTs grown with (B) 50 sccm CO, (C) 40 sccm CO, and (D) 30 sccm CO.

  • Fig. 5 Near-armchair SWCNT growth on CoxMg1−xO catalyst.

    (A) SEM of SWCNTs grown on CoxMg1−xO catalyst with 1% diluted CO at 700°C by ambient CVD. (B) TEM image of SWCNTs. (C) Chirality distribution of SWCNTs determined by nanobeam electron diffraction.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/12/eaav9668/DC1

    Fig. S1. Model of SWCNT growth following a screw dislocation theory.

    Fig. S2. Investigated SWCNTs (marked with arrows) and calculated growth rates.

    Fig. S3. SWCNT growth rate plots against tube diameter and catalyst size.

    Fig. S4. SEM images of carbon nanotubes grown on quartz-supported Co catalyst.

    Fig. S5. Chirality distribution histograms of SWCNTs grown on Co particles with different CO fluxes.

    Fig. S6. Chirality evolution and distribution of SWCNTs grown on Mo2C.

    Table S1. Growth rates and corresponding parameters of SWCNTs and catalysts for 16 different SWCNTs.

    Table S2. (n, m) populations of SWCNTs grown on Co catalyst using different flow rates of CO.

    Table S3. Chirality distribution of SWCNTs grown on Mo2C using different ratios of ethanol and H2.

    Movie S1. In situ observation of SWCNT growth.

  • Supplementary Materials

    The PDFset includes:

    • Fig. S1. Model of SWCNT growth following a screw dislocation theory.
    • Fig. S2. Investigated SWCNTs (marked with arrows) and calculated growth rates.
    • Fig. S3. SWCNT growth rate plots against tube diameter and catalyst size.
    • Fig. S4. SEM images of carbon nanotubes grown on quartz-supported Co catalyst.
    • Fig. S5. Chirality distribution histograms of SWCNTs grown on Co particles with different CO fluxes.
    • Fig. S6. Chirality evolution and distribution of SWCNTs grown on Mo2C.
    • Table S1. Growth rates and corresponding parameters of SWCNTs and catalysts for 16 different SWCNTs.
    • Table S2. (n, m) populations of SWCNTs grown on Co catalyst using different flow rates of CO.
    • Table S3. Chirality distribution of SWCNTs grown on Mo2C using different ratios of ethanol and H2.

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    Other Supplementary Material for this manuscript includes the following:

    • Movie S1 (.mp4 format). In situ observation of SWCNT growth.

    Files in this Data Supplement:

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