Ni-Mo and Co-Mo alloy nanoparticles for catalytic chemical vapor deposition synthesis of carbon nanotubes

Here, we show for the first time a catalytic chemical vapor deposition (CCVD) synthesis of carbon nanotubes (CNTs) using polyoxomolybdate clusters Mo12O28(mu(2)-OH)(12){Ni(H2O)(3)}(4) and Mo12O28(mu(2)-OH)(12){Co(H2O)(3)}(4) as a source of catalyst nanoparticles. X-ray diffraction analyses indicated that the products of thermal decomposition of the clusters contain NiMoO4 and CoMoO4 phases, which are converted into Ni-Mo and Co-Mo alloys at 900 degrees C in hydrogen environment. High-resolution transmission electron microscopy in combination with energy-dispersive X-ray spectroscopy confirmed the CNT growth from bimetallic nanoparticles. Synergism between two metals in an alloy resulted in large-scale production of non-bundled few-walled CNTs with narrow diameter distribution and high quality. (C) 2014 Elsevier B.V. All rights reserved.