KARPEN PILE

[profitis]

It looks like I will have to put up a demo myself

[pomodoro]

+1

Thanks Guys, I enjoyed the research, although it cost me a few dollars too many.  A few more tests to be done before I pack up, but I am totally convinced that complete removal of oxygen and any oxides from the cathode surface render these hydrogen karpens useless.  Absolutely for certain for the silver cathode. 

Electrochemically it makes sense,  the voltage of the inert silver initially shows that of the oxygen-OH/Water couple.  The kinetics of this is slow on silver  and takes a long time to be fully discharged.  Once all traces of oxygen have gone, the next dominant couple is hydrogen- protons/water, this voltage is that of the Pd/Pt , with some differences due to the slower kinetics on the silver, hence the low equilibrium voltage. 

Exactly why the other metals I tried were not as good as silver I don't know, but perhaps the oxygen doesn't adsorb on their surface as well or the hydrogen/proton couple is more active on their surface, reducing the dominance of the oxygen/OH- couple.

In all cases, once the oxygen is gone, power is gone too.  Any brown black coatings on the cathode should be avoided in tests as these could be slow reacting oxides that could power devices for weeks on end.

[profitis]

In direct contradiction to the research of chinese government laboratories @pomodoro.totaly stable Pt/Au,Pt(shiny)/Pt(black).

[profitis]

In direct contradiction to common sense too:all oxygen karpens eg. Ni/MnO2,Pt/Au,Ag/Ni,Ni/C,Pt/Pd,Ag/MnO2 etc totaly stable permanently

[profitis]

In direct contradiction to the textbooks too: silver hydrogen electrodes have a complete different voltage to platinum hydrogen electrodes according to your posted pdf on silver overpotentials