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Pt-Ru supported on carbon nanotubes (single-walled nanotubes, double-walled nanotubes (DWNTs) and multi-walled nanotubes) catalysts are prepared by an ethylene glycol reduction method. The Pt-Ru/DWNTs catalyst shows the highest specific activity for methanol oxidation reaction in rotating disk electrode experiments and the highest performance as an anode catalyst in direct methanol fuel cell single cell tests.

The high cost of Re has driven interest in processes for recovering Re from scrap superalloy parts. In this work thermodynamic modelling is used to study Zn-induced embrittlement of a superalloy and to direct experiments. Treating superalloy powder with Zn vapour reduces the average particle size after milling from approximatelym to 0.5–10 m, vs.m for untreated powder. Simulations predict the required treatment time to increase with temperature. Agreement between predictions and experiments suggests that an embrittling liquid forms in less than an hour of Zn vapour treatment between 950–1000 C and partial pressures of Zn between 14–34 kPa (2–5 psi). [ABSTRACT FROM PUBLISHER]

A technique to investigate the properties and performance of new multi-electron metal/air battery systems is proposed and presented. A method for synthesizing nanoscopic VB2 is presented as well as step-by-step procedure for applying a zirconium oxide coating to the VB2 particles for stabilization upon discharge. The process for disassembling existing zinc/air cells is shown, in addition construction of the new working electrode to replace the conventional zinc/air cell anode with a the nanoscopic VB2 anode. Finally, discharge of the completed VB2/air battery is reported. We show that using the zinc/air cell as a test bed is useful to provide a consistent configuration to study the performance of the high-energy high capacity nanoscopic VB2 anode.

Pt-Ru supported on carbon nanotubes (CNTs) (single-walled nanotubes, double-walled nanotubes (DWNTs), and multi-walled nanotubes) catalysts are prepared by an ethylene glycol reduction method. Pt-Ru nanoparticles with a diameter of 2-3 nm and narrow particle size distributions are uniformly deposited onto the CNTs. A simple and fast filtration method followed by a hot-press film transfer is employed to prepare the anode catalyst layer on a Nafion membrane. The Pt-Ru/DWNTs catalyst shows the highest specific activity for methanol oxidation reaction in rotating disk electrode experiments and the highest performance as an anode catalyst in direct methanol fuel cell (DMFC) single cell tests. The DMFC single cell with Pt-Ru/DWNTs (50 wt %, 0.34 mg Pt-Ru/cm(2)) produces a 68% enhancement of power density, and at the same time, an 83% reduction of Pt-Ru electrode loading when compared to Pt-Ru/C (40 wt %, 2.0 mg Pt-Ru/cm(2)).

A simple filtration method is developed to prepare a partially oriented superhydrophobic film of carbon nanotubes (CNTs) that have been catalyzed with uniform small Pt nanoparticles (2.8 nm) at high metal loading (30 wt %). A proton-exchange membrane fuel cell with the oriented CNT film as the cathode achieves higher single-cell performance than those with carbon black and a disordered CNT-film-based cathode probably because of the enhanced electrocatalytic activity of Pt/CNT and improved mass transport within the oriented film.

Deposition of small Pt nanoparticles of the order of 2-2.5 nm on carbon nanotubes (CNTs) grown directly on carbon paper is demonstrated in this work. Sulfonic acid functionalization of CNTs is used as a means to facilitate the uniform deposition of Pt on the CNT surface. The organic molecules attached covalently to the CNT surface via electrochemical reduction of corresponding diazonium salts are treated with concentrated sulfuric acid and the sulfonic acid sites thus attached are used as molecular sites for Pt ion adsorption, which are subsequently reduced to yield the small Pt nanoparticles. Cyclic voltammograms reveal that, after removal of the organic groups during high temperature reduction, these Pt nanoparticles are in electrical contact with the carbon paper backing. A typical Pt loading of 0.09 mg cm(-2) is achieved, that shows higher specific surface area of Pt than an E-TEK electrode with Pt loading of 0.075 mg cm(-2). A membrane and electrode assembly (MEA) is prepared with a Pt/CNT electrode as cathode and an E-TEK electrode as anode, and it offers better performance than a conventional E-TEK MEA.