Low-temperature synthesis of a nanostructured palladium-based catalyst with defined shape and its catalytic characteristics in methanol oxidation.

A new approach for the synthesis of highly active nanostructured catalysts on the surface of Pd-23%Ag films is proposed in order to intensify low-temperature (up to 100°C) hydrogen transport through hydrogen-selective palladium-containing membranes. The deposition of such catalyst significantly accelerates the surface stages of hydrogen transport (dissociative adsorption and recombinative desorption), that results in the increase of the hydrogen flux at low temperatures. It has been found that the formation of such functional coating is possible only if the current density during electrolytic deposition is lower than in classical methods and if a surfactant is added to the growth solution to facilitate the formation of a defined particle morphology. The developed nanostructured catalyst demonstrates a significant increase in catalytic activity in the reaction of alkaline oxidation of methanol, in comparison with palladium black. This is most likely due to an increase in the number of active sites in the material, compared with classical synthesis methods, which enhances the activity of the material with respect to reactions involving hydrogen. Evaluation of resistance to CO poisoning demonstrated the high efficiency of nanocatalysts. A chronoamperometry confirms the long-term stability and activity of the presented catalyst as well as the possibility of its practical use in catalytic and membrane applications.