Selective synthesis of thin carbon nanofibers: II. Over nickel-iron of nanoparticles prepared through burning of support

A very active nickel-iron catalyst for the efficient synthesis of thin CNF from an ethylene/hydrogen mixture was prepared through (i) dispersion of nickel and iron nitrates on carbon black (CB), (ii) successive combustion of CB at a selected temperature in air, and (iii) reduction in H-2 at 753 K. CNFs with diameter of 10-40 nm were produced in a high yield from ethylene/hydrogen (4:1) mixture by controlling the temperature or time for reduction of the mixed oxide in hydrogen. The reduction conditions of the oxide by hydrogen were critical to control the diameter and homogeneity of CNFs in the present synthesis procedure.