A study was made of so-called up-hill diffusion. The specimens were in the form of tubes or sheets, and H was introduced from the external surfaces. The permeation of H through the specimen was then monitored via changes in pressure within the tubes, or via the electrode potential across the 2 surfaces. In order to emphasize the up-hill diffusion effect, both membrane surfaces were coated with catalytically active Pd black. It was found that, when the membrane walls initially contained H, further increases in the H content at their outer surfaces could produce initial reductions in H pressure. The uphill effects could be satisfactorily explained in terms of overall expansions, of the interstitial sites, by H. This was associated with a Gorsky effect.

Y.Sakamoto, H.Tanaka, F.A.Lewis, X.Q.Tong, K.Kandasamy: International Journal of Hydrogen Energy, 1996, 21[11-12], 1025-32