Adsorption, diffusion, and permeation of hydrogen at PdCu surfaces

Abstract

Ab initio calculations have been utilized to comparatively study the adsorption, dissociation, diffusion, and permeation of hydrogen at FCC (111) and BCC (110) surfaces of Pd50Cu50. It is found that the adsorption of H2 on BCC (110) surface seems thermodynamically more stable with more negative adsorption energy than that on FCC (111) surface, while the dissociation energy of H2 on BCC (110) surface is much bigger. Furthermore, the BCC (110) or FCC (111) surface of Pd50Cu50 possesses much higher hydrogen permeability and lower hydrogen diffusivity than its corresponding Pd50Cu50 bulk. In addition, the BCC (110) surface of Pd50Cu50 should be preferred in actual applications as a result of its excellent hydrogen permeability. The present findings are in nice agreement with experimental results in the literature, and could deepen the comprehension of hydrogen permeation through PdCu membranes.