An Au/Fe2O3 catalyst prepared using a two-stage calcination procedure achieves target conversion and selectivity for the competitive oxidation of dilute CO in the presence of moist excess H2 and CO2.

5336partitioning in the case of this relatively small hydrophilic monocation compared to the distinct binding observed with the larger, more hydrophobic C B P underlines the role of hydrophobic factors and once again reinforces the idea that these cations as well as probably many other polar organic molecules are solubilized or J. Am. Chem. SOC. 1981, 103, 5336-5341 interact with micelles by binding at hydrophobic-hydrophilic interfaces.Abstract: A simple theory based on electrochemical principles is presented which predicts some of the catalytic properties of the widely used colloidal metal dispersions. The theory has been specifically applied to the case of photocatalytic water reduction to H2. The model assumes that the kinetic properties of the system are governed by the current-potential curves of the half-reactions and that the reaction velocity can be determined by finding the common potential at which the current attributable to the mediator (e.g., methyl viologen) oxidation is equal to that for proton reduction at the metal surface. The effects of pH, mediator potential, and colloid size and composition can be predicted. These predictions have been experimentally verified with methyl viologen radical cation generated electrochemically and photochemically (via the Ru(bpy)?+-N-phenylglyche system) and with other mediators at colloidal dispersions of several metals.

Au/Fe 2 O 3 catalysts prepared using co-precipitation are described and discussed for the preferential oxidation of CO in the presence of H 2 , H 2 O and CO 2 . A catalyst prepared using a two-stage calcination procedure (400 uC followed by 550 uC) achieves target conversion and selectivity (.99.5% CO conversion and .50% selectivity, based on O 2 , for the competing conversion of H 2 with O 2 at 80-100 uC) for the competitive oxidation of dilute CO in the presence of moist excess H 2 and CO 2 . The effect of the preparation method of the uncalcined precursor is described and the effects of calcination on the catalyst activity in the absence of H 2 , CO 2 and H 2 O is initially explored. The catalysts are characterised in detail using electron microscopy (TEM), X-ray photoelectron spectroscopy and Mo ¨ssbauer spectroscopy. For the target conversion to be achieved, it is necessary that the activity for the reverse water gas shift activity (CO 2 + H 2 A CO + H 2 O) of the catalyst is suppressed, since under the fuel cell conditions this reaction reforms CO at high CO conversions due to the presence of excess CO 2 and H 2 . It is proposed that the two stage calcination procedure removes active sites for the water gas shift reaction whilst retaining active sites for preferential CO oxidation.

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15 431 448 20 431 431 acetic acid-chloroform mixture.In almost all cases, 5 ml. of the solvents tested were miscible with 20 ml. of acetic acid-chloroform.Recovery of peroxide was quantitative when as little as 20% by volume of acetic acidchloroform was present in the solvent mixture. It should therefore be possible to determine peroxide groups on polymers and other organic solids if the solution of the material is compatible with the minimum amount of acetic acid-chloroform required for the reaction of the peroxide with iodide.Attempts to determine di-ferf-butyl peroxide by using HC1 to increase the acidity were unsuccessful. Ten milligrams of this peroxide gave a pale yellow 2 hours after solution in 1 to 1 HC1 and the addition of KI.