Black Pt effected the hydrogenation of Ru(COD)(eta(3)-C3H5)(2) (1; COD is 1,5-cyclooctadiene) by dihydrogen gas (pressure similar to 1 atm) at -10 degrees C in hexanes. The hydrogenation resulted in adsorption of Ru adatoms by the surface of Pt with concomitant formation of propane, cyclooctane, and small amounts of cis-bicyclo[3.3.0]octane and n-octane. Compound 1 did not react with dihydrogen gas under these conditions in the absence of Pt. The total amount of cyclooctane, bicyclo[3.3.0]octane, and n-octane in solution was equal to the amount of 1 consumed at all stages of the hydrogenation. The lifetimes of the organic fragments on the surface were short on the time scale of the hydrogenation. It was therefore possible to observe in real time both the stoichiometry and the activity of the evolving Ru-Pt surface by monitoring the concentrations of either 1 or the C-8 product hydrocarbons in solution. There was a kinetic burst during the initial stages of the hydrogenation that ended after deposition of 0.2-0.5 equiv of Ru versus Pt-surface (Pt-surface is an active site on black Pt). The rate decreased after the burst and then increased as more Ru was deposited on Pt to reach a maximum, constant rate after deposition of 1.5-1.8 equiv of Ru. Cyclic voltammograms recorded in 1.0 M H2SO4 of the bare surface, of the surface after adsorption of a monolayer of carbon monoxide, and of the surface in the presence of methanol showed that coverage of Pt by Ru was essentially complete after the maximum, constant rate was achieved during hydrogenation of 1. The surface area of a Ru surface resulting from hydrogenation of 2.7 equiv of 1 was 67% that of the original Pt surface according to the charge associated with oxidation of an adsorbed monolayer of carbon monoxide. Anodic stripping of Ru showed that the total of C-8 hydrocarbon products in solution after hydrogenation of 1 equaled the amount of Ru deposited on Pt. A catalyst surface resulting from hydrogenation of 0.11 equiv of 1 was up to similar to 14 times more active than bare Pt for the potentiodynamic oxidation of methanol ([MeOH] = 1.0 M, [H2SO4] = 0.5 M. 40 degrees C, sweep rate 5 mV/s). A catalyst surface resulting from hydrogenation of 0.33 equiv of 1 oxidized methanol potentiostatically at 0.158 V (vs SCE, [MeOH] = 0.5 M, [H2SO4] = 0.5 M, 25 degrees C) for 45 min with similar to 13 times the activity of Pt under the same conditions. A catalyst surface resulting from deposition of 0.8 equiv of Ru oxidized methanol potentiostatically at 0.256 V (vs SCE) under the above conditions for a total of 1.5 h with negligible dissolution of Ru into the electrolyte.