A New Approach to Modeling the Hydrogen Permeability of Pd-Based Membranes Taking into Account Surface Roughness

In this study, membranes based on palladium and its alloy with copper, capable of selectively transmitting hydrogen in the range of 25–500°C, were manufactured. Modification of the membrane surface by applying a nanostructured coating significantly expanded the operating capabilities of Pd membranes to low temperatures unattainable by analogs. This result was achieved by accelerating the limiting surface stages and, accordingly, shifting the influence of the diffusion stage toward lower temperatures. The obtained results were confirmed by data on the activation energy of the processes, according to which, due to surface modification, the activation energy was reduced by up to 2 times, compared to uncoated membranes. These results formed the basis for the mathematical model of hydrogen transport through Pd membranes at low temperatures developed in this study. This model takes into account the membrane surface roughness factor, which is an important criterion for the selected temperature range, where surface processes limit hydrogen transport. The obtained results suggest that the developed model is promising for predicting the efficiency of Pd-based membranes.