CATALYTIC INFLUENCE OF BIMETALLIC PHASES FOR THE SYNTHESIS OF SINGLE-WALLED CARBON NANOTUBES

Bimetallic systems of Co with Sn, Pd, Ru, Fe, Ni, W and Pt were studie d for the metal-mediated synthesis of single-walled carbon nanotubes ( SWT), and compared with Co alone. The materials were characterized by TEM, XRD and H-2 chemisorption. Sn, Ru, Fe and Pd decrease the catalyt ic effect of Co, whereas W or Ni have little effect on Co. By contrast , a synergy exists between Co and Pt for the SWT formation. The highes t SWT yield was obtained with Co/Pt = 3/1 (at/at), but the selective c atalytic phase is actually the definite CoPt compound identified by XR D. After activation at 673 K under hydrogen, 1/3 to 1/2 of the bimetal lic surface becomes accessible for hydrogen. The CoPt(3/1)/SWT composi te is active and selective for the liquid-phase hydrogenation of cinna maldehyde to cinnamyl alcohol.