The effect of spatial variation in potential energy on the diffusion in heterogeneous media

The standard equation of diffusion in heterogeneous media is found to be incomplete. The effect of heterogeneity on diffusion phenomena is commonly considered to be caused by only spatial variations of diffusion coefficient while the spatial difference in the potential energy of diffusing particles due to their interactions with the inhomogeneous medium is not taken into consideration. The possibility of new transport phenomena in heterogeneous media follows from the corrected equation. In particular the great increase of hydrogen permeability through the membranes of metallic alloy is turned out possible due to an optimization of spatial distribution of the alloy composition. •The standard equation of diffusion in heterogeneous media is found to be incomplete.•Spatial difference in the potential energy of diffusing particles is taken into consideration.•New transport phenomena in inhomogeneous media follow from the corrected equation.•Hydrogen permeability of membranes of metallic alloys can be greatly increased.