I am trying to perform the Hebb-Wagner technique to calculate the electron and proton transference number in metal oxide ceramic pellets. In Hebb-Wagner technique we should sandwich the sample (ceramic pellet in my case) between one ion-blocking electrode (e.g. stainless steel) and one reversible electrode to both ions (protons) and electrons to polarize the cell.

My question is what happen if we sandwich the sample between two ion-blocking electrode and perform the d.c. polarization?

Secondly, if we have to use reversible electrode on one side, what is the suitable reversible electrode for electrons and protons? Can we use the porous Pt mesh or porous carbon paper as a reversible electrode for both electrons and protons.