The Standard Hydrogen Electrode

A diagram of the standard hydrogen electrode is shown in figure 8. The actual electrode consists of a platinum black foil; usually square in shape attached to a platinum wire conductor. The platinum foil is immersed in a solution having hydrogen ions present at a concentration of 1 g ion per liter. There are various methods of ensuing the platinum black is saturated with hydrogen gas and one method is shown in figure 4.

Figure 8. The Standard Hydrogen Electrode

            Thus,  2H⁺  +  2e^–  ↔  H₂  E^o  =  0.0000- V  (by definition)   (23)

The output of the standard hydrogen electrode is independent of temperature but, unfortunately, due to the necessary use of gaseous hydrogen the device is not practically very useful.