Self-catalytic synthesis of hierarchical vanadium nitride/carbon superconducting nanocomposites

Abstract

An easy way to produce VN nanocomposites at relatively low temperature (800 °C) using simple precursors is presented. A self-catalytic growth approach has been developed for spontaneous preparation of superconducting VN/C nanocomposites composed of VN nanoparticles and well-defined carbon nanofibers. The carbon nanofibers were found to grow by a self-catalytic process through tiny VN nanocrystals. In this case, a homogeneous gel-like starting product has been formed that is converted by calcination into the corresponding metal nitride, without any preliminary treatments or further purification. The samples were characterized by XRD, TEM, SEM, and BET. The as-obtained nanocomposite shows an onset superconducting temperature at ∼9 K, which is similar to that reported for bulk VN. The procedure has been shown to be rather general and it was possible to open a new avenue toward the scale-up syntheses of other new transition metal nitride nanocomposites.