Synergism of C₅N Six-Membered Ring and Vapor−Liquid−Solid Growth of CN<i>_x</i> Nanotubes with Pyridine Precursor

Abstract

A series of bamboo-like CN(x)() nanotubes have been synthesized from pyridine precursor by chemical vapor deposition with bimetallic Fe-Co/gamma-Al(2)O(3) catalyst in the range of 550 approximately 950 degrees C. An unusual predomination of pyridinic nitrogen over graphitic nitrogen has been observed for the CN(x)() nanotubes with reaction temperature below 750 degrees C. The pyridinic nitrogen decreases and the graphitic nitrogen increases with rising reaction temperature. A synergism mechanism of C(5)N-six-membered-ring-based growth through surface diffusion and vapor-liquid-solid growth through bulk diffusion was accordingly deduced and schematically presented. This mechanism could not only explain our own experimental results, but also understand the CN(x)()-nanotube-related experimental phenomena in the literature, as well as be in accordance with the basic principle of diffusion kinetics. A promising route to the challenging topic for synthesizing regularly arranged C(5)N or high-N-content CN(x)() nanotubes has also been suggested.