Enhancement of the Electrocatalytic Activity of Gold Nanoparticles Towards Methanol Oxidation

By citrate reduction of HAuCl4, Au nanoparticles with a diameter of 15 nm and low polydispersity were synthesized. By deposition and subsequent dissolution of PbO2 in an alkaline medium, the particles were cleaned from their organic capping agents. The electrocatalytic behavior towards methanol oxidation under alkaline condition of these particles was found to be substantially enhanced by the cleaning procedure. The origin of the enhancement was studied by comparing the voltammetric profiles of the cleaned nanoparticles prior and after treatment with diluted nitric acid. The reason for the enhancement is mainly the removal of the organic shell. No hints of contributions of residual Pb and/or PbO2 from the cleaning process on the particle’s surface to the enhancement were found.