Electrochemical oxidation of methanol and ethanol on two-dimensional self-assembled palladium nanocrystal arrays

Abstract

The operating principle of direct alcohol fuel cells is based on the electrochemical oxidation of alcohols such as methanol or ethanol. Palladium nanocrystals are promising catalysts in the electrochemical oxidation of methanol and ethanol in basic media. We demonstrate the alignment of monodisperse palladium nanocrystals into two-dimensional arrays by self-assembly and the subsequent integration as catalysts for the electrochemical oxidation of methanol (MOR) and ethanol (EOR). The nanocrystal arrays exhibit high activity as a consequence of suppressed accumulation into bulk agglomerates, i e. minimized loss of active surface area. The resulting catalytic activity for the MOR and EOR on Pd nanocrystal arrays at the anodic oxidation peak achieve approximately 1040Ag−1 and 5500Ag−1, respectively (0.5M NaOH at a scan rate of 50mVs−1 with 1.0M alcohol concentration).