Combinatorial methods have been applied to the preparation and screening of fuel cell electrocatalysts. Hardware and software have been developed for fast sequential measurements of cyclic voltammetric and steady-state currents in 64-element half-cell arrays. The arrays were designed for the screening of high-surface-area supported electrocatalysts. Analysis software developed allowed the semiautomated processing of the large quantities of data, applying filters that defined figures of merit relevant to fuel cell catalyst activity and tolerance. Results are presented on the screening of carbon-supported platinum catalysts of varying platinum metal loading on carbon (and thus, particle size) in order to demonstrate the speed and sensitivity of the screening methodology. CO electro-oxidation, oxygen reduction, and methanol oxidation on a series of such catalysts reveal clear trends in characteristics and activities. Catalysts with smaller particle sizes reveal structure in the CO stripping voltammetry that can be associated with edge sites in addition to the closely packed planes, and this is concomitantly reduced as particle size is increased. Specific activity for steady-state methanol oxidation and oxygen reduction at room temperature in H(2)SO(4) electrolyte is found to be a maximum for the largest particle sizes, in agreement with the literature. These trends in activity are significantly smaller than the differences in activities of promoted platinum-based alloy catalysts for the same reaction.

We report the application of a new method for the high-throughput synthesis and screening of thin film materials and its application to the discovery of electrocatalysts. Results are presented for the PtPdAu ternary alloy system with respect to activity for oxygen reduction. The results reveal an enhancement in activity for a range of PtPd alloy compositions over either of the pure elements. An optimum composition range of ternary alloys with significant activity was also identified. A correlation was also investigated between the surface reduction potential and the activity for oxygen reduction in both binary and ternary alloys. The results demonstrate the potential of the methodology for the discovery and optimization of electrocatalysts for a wide range of applications.

Ru adatoms were deposited on black Pt gauze by hydrogenating Ru(COD)(η3-C3H5)2 (1, COD is 1,5-cyclooctadiene) over the gauze at low temperatures in hexanes solution under 1 atm of dihydrogen gas. A series of Pt−Ruad surfaces were prepared by interrupting the hydrogenation after deposition of 0.05, 0.10, 0.30, 0.32, 0.44, 0.70, and 3.5 equiv of Ru adatoms. The ratio of currents in the “double layer” to those in the “hydride” region in the potentiodynamic responses of these surfaces (0.5 M H2SO4, 25 °C, sweep range 0.025−0.70 V, 5 mV/s) increased as the equivalents of Ru adatoms increased. Stripping voltammetry of adsorbed monolayers of carbon monoxide from these surfaces (0.5 M H2SO4, 25 °C, sweep range 0.025−0.70 V, 5 mV/s) showed a drop by 120 mV in the CO stripping peak potential upon deposition of 0.05 equiv of Ru adatoms on Pt. Deposition of more Ru adatoms did not cause significant further drops in the CO stripping peak potential. The surfaces were evaluated as catalysts for the electrooxidation of MeOH. The measured currents were normalized to the specific surface areas of the gauzes measured before deposition of Ru adatoms by hydrogenation of 1. The order of activity of MeOH-poisoned Pt−Ruad surfaces toward the potentiodynamic oxidation of MeOH (0.5 M H2SO4, 25 °C, sweep range 0.025−0.60 V, 5 mV/s) was 0.05 > 0.10 > 0.30 ∼ 0.44 > 0.7 > 0 (Pt) equiv of Ru adatoms. The activity of Pt increased relative to the other surfaces as the potential increased, becoming more active than 0.30, 0.70, and 0.44 equiv Pt−Ruad at the upper limit of the sweeps. Surfaces with low equivalents of Ru adatoms (from 0.05 to 0.10 equiv) were the most active toward the potentiostatic oxidation of MeOH (E = 0.4 V, 0.5 M H2SO4, 0.5 M MeOH, 25 °C) with between 50 and 28 times higher turnover numbers than black Pt. The activation energies for oxidation of MeOH over 0.05 and 0.10 equiv of Pt−Ruad were 37 and 45 kJ/mol, respectively, at 0.4 V, 0.5 M H2SO4, and 0.5 M MeOH.

1) that reacted with an excess of dihydrogen gas (pressure H 2 ∼1 atm, ambient temperature) in THF and methylene chloride (∼5:1) to generate [Ru((R)-BINAP)-(H)(MeCN)(THF) 2 ](BF 4 ) (2). Reactions effected using 2 mol % 2 as catalyst include hydrogenation of (Z)-methyl R-acetamidocinnamate, hydrosilylation of ethyl acetoacetate by chlorodimethylsilane, tandem, stereoselective isomerization of (rac)-3-buten-2-ol via a partial kinetic resolution (ee of 3-buten-2-ol 42% S at 50% conversion) to initially generate (Z)-2-buten-2-ol, followed by isomerization of the enol to 2-butanone, and competing isomerization and intramolecular hydrosilylation of dimethyl-(2-propen-1-oxy)silane.

A study of the lithium ion conductor Li(3x)La(2/3-x)TiO(3) solid solution and the surrounding composition space was carried out using a high throughput physical vapor deposition system. An optimum total ionic conductivity value of 5.45 × 10(-4) S cm(-1) was obtained for the composition Li(0.17)La(0.29)Ti(0.54) (Li(3x)La(2/3-x)TiO(3)x = 0.11). This optimum value was calculated using an artificial neural network model based on the empirical data. Due to the large scale of the data set produced and the complexity of synthesis, informatics tools were required to analyze the data. Partition analysis was carried out to determine the synthetic parameters of importance and their threshold values. Multivariate curve resolution and principal component analysis were applied to the diffraction data set. This analysis enabled the construction of phase distribution diagrams, illustrating both the phases obtained and the compositional zones in which they occur. The synthetic technique presented has significant advantages over other thin film and bulk methodologies, in terms of both the compositional range covered and the nature of the materials produced.