Underpotential deposition, in electrochemistry, is a phenomenon of electrodeposition of a species at a potential less negative than the equilibrium potential for the reduction of this metal. The equilibrium potential for the reduction of a metal in this context is the potential at which it will deposit onto itself.

What is hydrogen Underpotential deposition?

On noble metals like Pt, Pd, Rh, Ru and Ir hydrogen adsorption takes place at the potentials more positive than the hydrogen evolution equilibrium potential. This so-called hydrogen underpotential deposition indicates strong interaction between hydrogen and the metal.

What is under potential?

Underpotential deposition (UPD), in electrochemistry, is a phenomenon of electrodeposition of a species (typically reduction of a metal cation to a solid metal) at a potential less negative than the equilibrium (Nernst) potential for the reduction of this metal.