Composite nanoscale electrodes for the study of electrocatalytic hydrogenation at palladium.

摘要

Well-ordered, nanoscale composite electrodes using template synthesis have been successfully constructed. The electrodes consisted of organic (alkyl carboxylic acids), inorganic (aluminum oxide) and metallic (palladium) components. Maximal homogeneity of the palladium deposits was obtained through manipulation of the metal precursor concentration, solution pH and the application of pulsed applied current waveforms rather than constant applied currents. Fabricated electrodes were characterized using scanning electron microscopy and the variability of pore-filling depths in the template was found to be less than 20%, which compares well with values reported in the literature.;Fabricated well-ordered Pd/Al203 composite electrodes were used to successfully convert phenol to cyclohexanone by electrocatalytic hydrogenation in an organic carboxylic acid buffer solution. Production of the secondary hydrogenation product cyclohexanol from the produced cyclohexanone was not observed. In contrast to powdered composite electrode systems reported in the literature, the functionalization of the alumina support with organic acids was found to have no effect on the reaction efficiency. This suggests that the fabricated ordered composite electrodes do not operate under the same constraints as the powdered-catalyst system upon which the model we were studying was based.