Influence of tungsten on the carbon nanotubes growth by CVD process

M. ESCOBAR; G. RUBIOLO; M. MORENO; S. GOYANES; R. CANDAL

JOURNAL OF ALLOYS AND COMPOUNDS

Elsevier Science

Año: 2009 vol. 479 p. 440 - 444

0925-8388

The effect of tungsten on the multi-walled carbon nanotubes (MWNTs) growth in CVD process over metal Fe-W catalyst included into a silica matrix is reported. A molar content of W in Fe/SiO2 up to 10 was studied. The incorporation of only 2% of tungsten modifies substantially the crystalline phases and the crystalline degree of the catalyst during the MWNTs synthesis. This fact seems to have a strong influence in the type and yield of the carbonaceous species obtained by chemical vapor deposition of acetylene, at 600ºC and 180 torr, over each catalyst. Tungsten interacts with iron within the matrix, diminishing the catalytic activity of the metal nanoparticles, and both, carbon nanotubes and carbon nanofibers, are obtained when tungsten is present. Results support the hypothesis of a base growth model for carbon nanotubes indicating a strong interaction between silica matrix and Fe/W nanoparticles, independently of the content of tungsten.