Knowledge Base

SHE, RHE, NHE hydrogen electrode

Source:Corrtest Time:2021-12-02 View:1298
SHE, RHE, NHE hydrogen electrode
SHE is the standard hydrogen electrode potential, which is defined as the potential of platinum in a solution with H ion activity of 1 and the partial pressure of hydrogen at 1 atmosphere. SHE is theoretical, ideal, and does not exist in reality, because there is no solution with H ion activity of 1 in the real system.

NHE is normal hydrogen electrode potential, and its definition is basically similar to SHE. But the condition is the H ion concentration is 1 instead of the H ion activity of 1. In reality, H ion concentration of 1 can exist. But the definition of NHE has been abolished;

RHE is reversible hydrogen electrode potential. It is defined as the potential of platinum in the solution of any pH value, not limiting to the H ion concentration of 1 (pH=0), and the partial pressure of hydrogen is 1 atmosphere. RHE electrode potential is widely used in present literatures.
For example, the saturated calomel electrode potential 245 mV is relative to SHE and does not change with the pH, but the RHE potential changes with the pH. RHE=245 mV+59 mV*pH, RHE= SHE (0) +59 mV*pH. Please note that 59 mV is conditional.

 

Home  About Us  Potentiostat/Galvanostat  Accessories  Support  Contact Us  

Copyright By © 2008-2021 Wuhan Corrtest Instrument Corp., Ltd