MORPHOLOGIES OF CARBON NANOCOILS/MICROCOILPREPARED BY CVD USING Al2O3-SUPPORTED METALCATALTST

摘要

The chiral single-helix carbon nanocoils with the fiber diameter of 30-300 nm, inner coil diameter of 0-100 nm, coil gap ofrn0-400 nm, were prepared by the catalytic pyrolysis of acetylene under the presence of Al2O3-supported metal catalysts, and thernreaction conditions, morphology, microstructure and growth mechanisms were examined. Ni metal was mainly used as the catalyst.rnThe thickness of coil layer was 1-3 mm after 1 hr at 750rn7500C and the content of nanocoils in the deposits was 70-100%. The carbonrnnanocoils were generally a single-helix coil such as α-helix proteins while carbon microcoils were double helix such as a DNA.rnThere is two types of coiling patterns, right-hand chiral and left-hand chiral. However, a lot of coils in which the chiral direction andrncoil axis change for many times were observed. The fin-like thin films with 20-30 nm high were sometimes observed on the carbonrnnanocoils. The new growth mechanism, based on the detail observation of the morphology and of the effect of electromagnetic field,rnof the carbon nanocoils will be present. Furthermore, some properties, such as electromagnetic absorption properties and sensorrncharacteristics, of the carbon nanocoils will be present.