Polyaniline-Supported Atomic Gold Electrodes: Comparison with Macro Electrodes

Under precisely controlled conditions, atomic gold electrodes with even or odd number of Au atoms per polyaniline repeat unit (Pt/PANI/Au (N) for 0 < N < 7) were prepared. The electrochemical behavior of these new electrodes is compared with that of macro gold and PANI coated platinum electrodes by testing electrochemical oxidation of n-propanol and iso-propanol. This study allowed us to separate the behavior dominated by that of macroscopic gold in strongly alkaline medium and by that of the quantized odd-even effect of atomic gold. Within this overarching scope, there is a specific oxidation pattern attributable to the structural differences between the two isomers of propanol. The significance of this research lies in the recognition of high specific catalytic activity of atomic gold, which is at least three orders of magnitude higher than that of bulk gold for the oxidation of alcohols. It points to a substantial saving of the precious metal without the loss of catalytic activity, which is important in fuel cells and in other energy conversion device applications.