Dear all,
While use the pseudo reference electrode, internal reference need to introduce. In the non-aqueous electrochemical system, ferrocene is most used in literature.
However, in aqueous system, pseudo reference electrode and internal reference are barely mentioned. Is there any good way to find an internal reference species?
thanks a lot
For aqueous electrochemistry the internal reference is not needed. The potentials of most common reference electrodes (Ag/AgCl, Hg/Hg2Cl2, Hg/HgO, Hg/Hg2SO4) are very stable and well-defined in aqueous systems. The need for additional (internal) reference in non-aq. systems is because there are no good reference electrodes for non-aq. The silver wire is commonly used, but the potential of a silver wire varies depending on the solvent and electrolyte.
If you really want an internal reference for aq. Echem, you could use a "redox probe" system such as Fe(CN)6 or Ru(NH3)6.
If you're working in alkaline media (pH >11) I would recommend the Hg/HgO RE for stability. But the most common aq.-RE is Ag/AgCl. If your system is sensitive to Cl- ions, don't use Ag/AgCl - or at least use a high quality double junction RE. You could also use a reversible hydrogen electrode (RHE) if you have the custom glassware.
Feel free to follow-up with Q&A. Good luck!
For aqueous electrochemistry the internal reference is not needed. The potentials of most common reference electrodes (Ag/AgCl, Hg/Hg2Cl2, Hg/HgO, Hg/Hg2SO4) are very stable and well-defined in aqueous systems. The need for additional (internal) reference in non-aq. systems is because there are no good reference electrodes for non-aq. The silver wire is commonly used, but the potential of a silver wire varies depending on the solvent and electrolyte.
If you really want an internal reference for aq. Echem, you could use a "redox probe" system such as Fe(CN)6 or Ru(NH3)6.
If you're working in alkaline media (pH >11) I would recommend the Hg/HgO RE for stability. But the most common aq.-RE is Ag/AgCl. If your system is sensitive to Cl- ions, don't use Ag/AgCl - or at least use a high quality double junction RE. You could also use a reversible hydrogen electrode (RHE) if you have the custom glassware.
Feel free to follow-up with Q&A. Good luck!
Ag/AgCl(sat. KCl), saturated calomel electrode these are the most widely used reference electrode in aqueous system. So you need not to introduce in pseudo reference electrode. Moreover you can anytime convert the applied potential into standard hydrogen reference electrode just by adding the constant standard potential of your reference electrode with your applied potential.
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