STUDIES ON THE ELECTROCATALYTIC REDUCTION OF ALIPHATIC-ALDEHYDES ON PALLADIUM-MODIFIED CARBON-PASTE ELECTRODES

Carbon paste electrodes modified either by mixing palladium powder to the electrode material or by electrodepositing Pd via cycling the pote ntial between 0.4 and, -0.7 V (versus SCE), exhibited stable electroca talytic response for aliphatic aldehydes and aliphatic alcohols. The a ldehydes (e.g., formaldehyde) could be reduced to the corresponding al cohols (e.g., methanol), and the alcohols (e.g., methanol) could be ox idized to the corresponding aldehydes (e.g., formaldehyde) by direct c urrent voltammetry (DCV). The electrocatalytic effect was attributed t o the electrogenerated metallic palladium at the electrode surface. Th e cathodic current peak, the height of which was proportional to the a ldehyde concentration, had negative values; it was ascribed to a desor ption of the product of the electrode reaction from the surface of the electrode. This peak was used for quantitative analytical purposes.