Nano-structure Of The Palladium Thin Layer Of Methanol Electro-catalytic Oxidation Studies

The electrocatalytic oxidation of methanol is an important part in the application of fuel cells based on oxidation of small organic molecules. The bulk Pt and Pt nanoparticles are used most extensively as the catalysts in the fuel cells based on oxidation of small organic molecules. However, they often suffer from the poisoning effect caused by the generation of strongly chemisorbed intermediates like CO. Pd and Pd-based materials have provided an enhanced effect to oxidation of formic acid and suppressed the poisoning of chemisorbed intermediates, which enables them to act as a prospective alternative catalyst for electro-oxidation of small organic molecules in fuel cells.Nanostructured Pd thin films are directly formed on polycrystalline Pt and Au substrates in the absence of hard and soft templates by using a cyclic potential sweep technique, which is confirmed by both SEM observation and their unusual cyclic voltammetric characteristics in H2SO4 solution. Interestingly, the bimetallic electrodes obtained after the deposition of ultrathin Pd films onto Pt and Au substrates display much higher catalytic activity towards the electro-oxidation of methanol than the bulk Pt electrode. Besides, it is found that the foreign metal substrate has great influence on the electro-catalytic behavior of the Pd films.The main research contents and results are summarized as follows:(i) Selecting an ideal electrolyte and establishing a good deposition method to prepare the nanostructured Pd thin films on electrodes,(ii) Voltammetric characterization and SEM characterization of Pd thin film modified Pt and Au electrodes,(iii) Electro-catalytic activity of tha Pd/Pt and Pd/Au electrodes towards the oxidation of methanol.