Carbon nanotubes production over Co/silica catalysts

For the catalytic synthesis of carbon nanotubes having fullerene-like diameters, a detailed description of the catalyst preparation is given. Silica-supported catalyst samples (prepared from Co-acetate solution of different pH) were tested in the decomposition of acetylene. Catalysts with various pretreatments (different calcination temperature, time and atmosphere) were compared in the carbon nanotubes production and characterized by X-ray photoelectron spectroscopy (XPS). The quality and the quantity of the buckytubes were studied by transmission electron microscopy (TEM). As a final conclusion, it is possible that changing the pH of the solution during catalyst preparation allows control of the quality of the carbon nanotubes, namely the amount of turbostratic straight and helical tubes.