Nor is there any internet info that can show that such spillover is irreversable @sarkeizen.I find that intensely suspicious.you must remember..karpen was also playing with hydrogen cells..open up dogaru and cazacu's referance at the bottom of the wikipedia article on karpen.

Platinized platinum will have to do for our future hydrogen experiment then @pomodoro.if it was platinized by the manufacturer company then it will do fine.if it was platinized by you then alot will depend on your platinizing skills because the platinum black must be totaly adherent and conducting straight onto the underlying foil. Karpen did not use benzene in figure 2. He used one single electrolyte and so did I in my series of tests a few years back.take a solution of sodium hydroxide under air and touch the surface with the bottom end of a PLATINIZED(black) platinum foil.take a aqua regia etched smoothish platinum foil and immerse it totaly under the electrolyte next to your platinized cathode.you will now get perpetual current bursts in the region of 50-100 micro-amps/cm2 if you do this properly. The surface platinized electrode is your cathode(+).the submerged non-platinized foil is your anode(-). this is an oxygen gas concentration cell.the nernst equasion applies.the larger you make your anode and cathode the larger your current.voltage is about 0.1-0.2v

Ah OK now I understand. You believe karpen's cell woks because the pt concentrates oxygen from air, due to its nature, and the gold does not, thus a concentration cell is formed.  So, if I have a working model in air and put it under vacuum absolutely no current would flow, correct?

I'll devote some time from wed next week constructing one of these cells and test the voltage & current in O₂, Ar, and H₂ atmospheres. I'm still going to check gold as well, want to check its potential vs pt in deoxygenated dil sulfuric.

Mr profitis , for the top electrode of your requested test with hydrogen, the expected E_H at 25C is 0-0.059log(pH₂^1/2/[H⁺]) which satd. with H2 would have p=1, but the distant electrode has p=0, any idea of the potential there before any hydrogen reaches it?

Yep, makes sense,  I just found an interesting paper http://pubs.acs.org/doi/abs/10.1021/j150543a032regarding some H overpotential studies in NaOH, it even used platinized Pt as a reference.  I should be able to get the full article on wednesday, to keep as a reference as my tests progress.

Its important to note that there's a line between a concentration cell and a spillover cell eg. I can take two exact same Pt smooth or black foils and put them in the setup and get a strictly nernstian voltage.if we take two different inert metals then it becomes a more spillover-induced voltage for reasons other than concentration and more towards overpotential.

I was thinking the same thing mr pomodoro.either their research ended in stalemate due to cost/benefit ratio or their research continued,deep underground.perhaps things have been shelved I don't know.catalyst spillover is also a recently discovered phenomena so the connection would have been made very recently or not at all.nontheless we can take credit for this with a few simple experiments.