Unlike the standard hydrogen electrode, its measured potential does change with the pH, so it can be directly used in the electrolyte.
[1][2][3] The name refers to the fact that the electrode is directly immersed in the actual electrolyte solution and not separated by a salt bridge.
The potential of the RHE correlates to the pH value: In general, for a hydrogen electrode in which the reduction of the hydronium ions (H3O+) occurs: or, more often commonly written simply with H+ denoting H3O+: with, the equilibrium potential E depends on the hydrogen pressure pH2 and the activity aH+ as follows: Here,
This means that the required cell voltage is higher than the equilibrium potential because of kinetic limitations.
The term refers to a hydrogen electrode immersed in the electrolyte solution actually used.