P alladium based membranes are used to produce high-purity hydrogen. One of the ways to modify the membrane surface is to create a nanostructured layer using powdered hydrogen chemisorbing substances. The aim of this study has been manufacturing of resistant to long-term use palladium containing films, modified with a pentagonally structured nanoflower-typecoating, capable of transferring hydrogen at low temperatures. This will reduce energy costs in the process of obtaining high-purity hydrogen, as well as use the developed membranes to create a hydrogen electrode of an oxygen-hydrogen fuel cell operating at low (0-100°C) temperatures. During the study two methods of surface modification have been obtained: the classical method of palladium black "nanoparticles" and the new author's method "nanoflower". Pentagonally structured palladium nanocrystalliteshave been obtained by the electrochemical method from a working solution containing a surfactant (tetrabutylammonium bromide). A necessary condition for obtaining such structures has been a reduced current density compared to the classical palladium black method. Thin palladium-silver films with a thickness of 10 μmhave been modified on both sides by the developed coatings. After that, the films as membranes have been studied in the processes of hydrogen permeability. The values of the hydrogen flux for membranes modified by the "nanoflower" method are approximately 1.8 times higher than those for membranes obtained by the classical palladium black method. An important feature of the experiment has been the increased flux despite the reduced real surface area. The feature has been recorded in membranes with a lower roughness, but with a pentagonally structured surface organization. This have occurred contrary to the classical concepts of acceleration of the surface stages of hydrogen transport, which indicate that there is no alternative to an extensive increase in the development and specific surface area of palladium membranes.
Share this page on your timeline