Metal-nanocluster-filled carbon nanotubes: Catalytic properties and possible applications in electrochemical energy storage and production

Ensembles of highly aligned and monodisperse graphitic carbon nanotubules h ave been prepared via the template method using chemical vapor deposition o f carbon within the pores of alumina membranes. Tubules with diameters of 2 00 nm have been prepared, and smaller diameters are possible. Free-standing aligned carbon-tubule membranes are formed by this template method. These novel carbon tubule membranes can be filled with nanoparticles of electroca talytic materials (i.e., Pt, Ru, Pt/Ru), which can then be used to electroc atalyze O-2 reduction and methanol oxidation as well as the gas-phase catal ysis of hydrocarbons. Hence, these membranes have potential applications in fuel cell development. Smaller, highly ordered graphitic-carbon tubules ca n also be prepared within the template-synthesized carbon tubules, using Fe nanoparticles as catalysts. In these novel tube-in-tube structures, both t he outer and the inner tubules are electrochemically active for Li+ interca lation, suggesting possible applications such as Li ion battery anodes.