Hydrogen transport through Mo2C/PdCu composite membranes

Abstract

First-principle calculations have been adopted to systematically investigate the adsorption and dissociation of H2 on Mo2C (100) and (001) surfaces, as well as the fluxes of hydrogen dissociative adsorption on the Mo2C surfaces and the hydrogen across the Mo2C(100)/PdCu(110) and Mo2C(001)/PdCu(110) interfaces. It is observed that the adsorption and dissociation of H2 as well as the hydrogen flux on the Mo2C (100) surfaces are energetically more favorable than on the Mo2C (001) surfaces. Calculations also reveals that the hydrogen flux across the Mo2C(100)/PdCu(110) and Mo2C(001)/PdCu(110) interfaces is one and six order of magnitude greater than the hydrogen desorption flux on the permeation side of PdCu, respectively. In other words, the hydrogen diffusion in BCC PdCu bulk and hydrogen desorption are the dominant steps of hydrogen transport through Mo2C/PdCu composite membranes, rather than the hydrogen diffusion across the Mo2C/PdCu interfaces. The calculational findings are consistent with the similar experimental observations in the literature, and provide a profound understanding regarding the hydrogen transport across Mo2C-coated PdCu membrane.