Atom-scale Calculation Of Hydrogen Permeation In Cu-Pd Alloys

In recent years, due to the world’s oil depletion, hydrogen has received a widespread attention as an alternative to fossil energies. Palladium-based alloy membranes are now widely used in the hydrogen separation and purification techniques. How to find proper Pd-based alloys to resist poisoning from sulfur and unsaturated carbon compounds, while retaining the desired properties of pure Pd membranes is very important to the membranes design. Rapid development in computer technology and computational materials science lay the foundation for theoretical simulation for hydrogen permeation. This work proposed a combined atomic scale computational method to predict hydrogen’s permeability in Pd-Cu alloy membranes.Theoretical calculation of the hydrogen permeability mainly consists of three parts:(1) Calculations of various physical properties of hydrogen atoms in alloys (binding energy, the zero-point energy and transition state, etc.) by special quasi-random structure theory and First principles methods;(2) Establishment of composition dependent local cluster expansion models to accurately predict the hydrogen properties mentioned above in an overall alloy composition range;(3) Analysis of hydrogen solubility and diffusion mechanism in different alloy compositions by Sievert’s Law and Kinetic Monte Carlo Simulation.This method gives a thorough understanding of hydrogen’s thermodynamic and kinetic properties in Pd-Cu alloys from the atomic scale, and accurately predicts hydrogen permeability under different alloy compositions and temperatures. What’s more, the theoretical predictions agree well with experimental results, indicating that the method proposed in this work can be used to theoretically evaluate the performance of alloy thin-films and assist metal membranes design in hydrogen purification. There are30figures,6tables and66references in this paper.