Interpretation of Hydrogen Permeation

of course, necessary to test the hydrogen flux in a real membrane under realistic conditions. This can also give significant information on transport processes in the material. It can even be the only way to measure hydrogen transport in materials where, for example, electronic conductivity is so high that transport number measurements by the EMF method or other electrical methods are impossible. 

Deuterium on the feed side may be used to better separate permeated hydrogen from background sources. 

Water vapor may play an important role. Firstly, water vapor is in many cases the actual source of the protons in the membrane material. Thus, a hydrogen-permeable oxide may simply not work in dry gases. Secondly, water vapor determines the oxygen activity, and the membrane may be unstable in dry hydrogen. Thirdly, the water vapor may be used to set up or to balance out an oxygen activity gradient It may also affect the electronic conductivity. Normally, it is good practice 

For experimental studies we refer to the references in the literature section below. 

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