CO oxidation at platinum-molybdenum electrodes

CO oxidation at Pt-Mo electrodes prepared by different procedures is studied. When CO is oxidized from its saturated solutions at Mo-containing electrodes, catalysis is observed at lower potentials (<0.4 V (RHE)); inhibiting, at higher potentials (>0.7 V). When adsorbed CO is oxidized in supporting electrolyte, no oxidation current is observed at lower potentials; the current observed on platinum at higher potentials (>0.7 V) is also lowered in the presence of molybdenum. Depending on the preparation procedure, catalysts with different phase structure were obtained, namely, as the Pt and Mo separate phases, alloys with the platinum-type crystal lattice, or mixed amorphous deposits. The catalyst phase structure did not affect the general picture of observed processes; however, it had influence on the magnitude of the catalytic and inhibiting effects. The presence of crystallinity made the catalyst more stable against oxidation. Amorphous structures were unstable during the potential cycling and the catalyst storage.     

Tolerant-to-methanol cathodic electrocatalysts based on organometallic clusters

A new approach to the fabrication of catalytic systems based on hetero-and homometal-chalcogenide clusters of Pt-M-X type (M: Fe, Mn; X: S, Se, Te), which provides the reproducibility of catalyst composition and uniform distribution of catalyst over the carbon support, is proposed. Thus obtained catalysts are characterized using the XRD, TEM, and EDAX methods. The electrocatalytic activity of these systems in the oxygen reduction reaction, the role of the nature of chalcogenide atom and the atom of the second metal, which is the platinum partner, and the electrochemical behavior of nonplatinum chalcogenide systems are studied.     

Syntheses and reactions of some fluorinated dienes,cyclobutenes and furans

There are many reports¹ of the pyrolysis of fluorinated organic compounds, including the defluorination of cyclic fluorocarbons over iron to give aromatic compounds. Extending this technique we have investigated the flow pyrolysis of some readily accessible unsaturated fluorocarbons, such as I, II, and III, and found these to be synthetically

useful routes to fluorinated dienes, cyclobutenes, and furans. Pyrolyses were carried out using a nitrogen flow over platinum, iron or caesium fluoride heated at 430–700°. The various products can all be rationalized in terms of intermediate allylic radicals, and the solid substrate influences which allylic radicals are formed.We are also investigating the chemistry of those now accessible compounds, such as IV, V, and VI, and some of the preliminary results are described.

For example the fluoride ion induced dimerisation of IV gave two major products VII and VIII via a particular interesting mechanism.