Investigation of the electrochemical reactivity of benzyl alcohol at platinum and palladium electrodes

The electrochemical reactions of 2 mM benzyl alcohol (BA) on platinum and p alladium electrodes in 0.1 M HClO4 were studied by means of differential el ectrochemical mass spectrometry (DEMS) and cyclic voltammetry. The objectiv e of this work is to investigate the influence of electrode nature on the r eactivity of BA. On-line mass spectroscopy analysis of volatile products re veals that the interaction of BA with these metals partially occurs dissoci atively producing benzene. CO2 is the sole oxidation product detected. The corresponding mass signal exhibits three different contributions. The exten t of each contribution is found to depend strongly on the electrode nature, though in the case of palladium, it also varies with changes in the electr ode potential range covered during the voltammetric scan. The different cat alytic activity of platinum and palladium is demonstrated during the electr oreduction process. Both hydrogenolysis of the molecule and hydrogenation o f the aromatic ring occur on platinum, whereas the latest process is of lit tle significance on palladium. (C) 2000 Elsevier Science Ltd. All rights re served.