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Proton-exchange membrane fuel cells (PEMFCs) are expected to provide a complementary power supply to fossil fuels in the near future. The current reliance of fuel cells on platinum catalysts is undesirable. However, even the best-performing non-noble metal catalysts are not as efficient. To drive commercial viability of fuel cells forward in the short term, increased utilization of Pt catalysts is paramount. We have demonstrated improved power and energy densities in a single PEMFC using a designed cathode with a Pt loading of 0.1 mg cm−2 on a mesoporous conductive entangled carbon nanotube (CNT)-based architecture. This electrode allows for rapid transfer of both fuel and waste to and from the electrode, respectively. Pt particles are bound tightly, directly to CNT sidewalls by a microwave-reduction technique, which provided increased charge transport at this interface. The Pt entangled CNT cathode, in combination with an E-TEK 0.2 mg cm−2 anode, has a maximum power and energy density of 940 mW cm−2 and 2700 mA cm−2, respectively, and a power and energy density of 4.01 W mgPt−1 and 6.35 A mgPt−1 at 0.65 V. These power densities correspond to a specific mass activity of 0.81 g Pt per kW for the combined mass of both anode and cathode electrodes, approaching the current US Department of Energy efficiency target. [ABSTRACT FROM AUTHOR]

Abstract: Both single-wall or multi-wall nanotube growth result in a soot-like material that contains the desired product. The selective recovery of the nanotube product from this soot still represents a challenge. Methods to date either result in chemical modification of the nanotubes themselves, are time consuming or use expensive to produce polymers. Using a variety of biomolecules, we have been able to selectively suspend multi-wall carbon nanotubes in aqueous solutions while leaving behind the extraneous by-products in the precipitate. At comparable biomolecule to soot ratios, all biomolecules selectively retained more nanotubes than an organic polymer previously used to purify multi-wall nanotubes (PmPV—poly m-phenylene-co-2,5-dioctoxy-p-phenylenevinylene). The highest recovery as determined by Electron Paramagnetic Resonance was 56% of the available nanotubes. The method provides a simple, one-step, non-destructive purification process that facilitates the formation of pure multi-wall carbon nanotube containing biodispersions. [Copyright &y& Elsevier]

Carbon nanotubes (CNTs) were stabilized in solution through sonication-induced polymerization of acrylated epoxidized soybean oil (AESO) monomer. Transmission electron microscopy and atomic force microscopy showed that the resulting polymer coatings of nanotubes in solution were approximately 10–30 nm in thickness. Raman spectroscopy suggests that AESO intercalates Nanocyl bundles and coats the exterior of HiPco bundles. Using sonication a stable dispersion of as-produced carbon nanotube powder was formed. Mechanical measurements on macroscale composites samples showed modulus enhancement consistent with a lower bound rule of mixtures. [ABSTRACT FROM AUTHOR]

A novel Si-MWNT nanocomposite synthesized viaa CVD process shows a high reversible capacity of over 1500 mAh g−1and stable cycling performance, which can be ascribed to the maintenance of a good conductive network by means of the direct scattered growth and pinning of MWNTs on Si particles. [ABSTRACT FROM AUTHOR]

Examines the interconnection of multiwall carbon nanotubes (SWNT) with a ruthenium complex through amide linkage. Molecular structure of SWNT; Covalent attachment of the ruthenium compound with SWNT; Carbon nanotube functionalization.