No abstract

Single-wall carbon nanohorn (SWNH) aggregates can be produced by CO 2 laser vaporization of carbon, and a single aggregate can take either a "dahlia-like" or "bud-like" form. We found that "dahlia-like" SWNH aggregates were produced with a yield of 95% when Ar at 760 Torr was used as the buffer gas, while "budlike" SWNH aggregates were formed with a yield of 70 or 80% when either He or N 2 at 760 Torr was used. The internal structures of both aggregates were studied by partially burning them in an O 2 atmosphere. We were then able to examine the mechanism for the formation of SWNH aggregates.

Open single-wall carbon nanohorns (SWNHs) were compressed repeatedly at 50 MPa to generate a nanocarbon material of high bulk density. TEM observations and Raman spectroscopy revealed a significant distortion in the structure of the compressed SWNHs. The obtained nanostructured disordered carbon exhibits a high methane storage capacity, reaching 160 cm 3 /cm 3 of nanocarbon at 3.5 MPa and 303 K. Comparison of the experimental results with grand canonical Monte Carlo simulations indicates the importance of the adsorption in the interstitial channels for the high total adsorption capacity of the generated nanostructured carbon.