Microstructural features of Co-filled carbon nanotubes

Cobalt-filled carbon nanotubes (CNTs) were prepared in situ in the decomposition of benzene over Co/silica-gel catalysts. Transmission electron microscopy (TEM) investigation showed that the products contained abundance of carbon nanotubes and most of them were filled with metallic nanoparticles or nanorods. High-resolution TEM (HRTEM), selected area electron diffraction (SAED) patterns and energy dispersive X-ray spectroscopy (EDS) confirmed the presence of Co inside the nanotubes. The encapsulated Co was further identified as α-Co with fcc structure, which frequently consists of twinned boundaries. Based on the experimental results, a possible growth mechanism of the Co-filled nanotubes was proposed. [Copyright &y& Elsevier]