Energetics of the system in which Red in solution is
oxidised to Ox in solution + ne- on the metal.
To the plot of the chemical component [molar chemical
standard free energy - (𝐺cO ) ] the electrical componet is
added to give the electrochemical molar free energy (𝐺).
The corresponding j vs. E curve is also traced by
interpolation of the different situations considered
In the first plot, at E = E°, the molar electrochemical standard free energy (𝐺 0) is reported
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺0
E = E0
reaction coordinate
j / mA
300
200
10-5
j0 =
A
a = 0.5
100
0
-400
400
-300
300
-200
200
-100
100
100
-100
0
200
-200
300
-300
h / mV
-100
-200
-300
400
-400
E = E0
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺
E1 > E0
reaction coordinate
j / mA
300
200
j0 = 10-5 A
a = 0.5
100
-400
400
-300
300
-200
200
-100
100
0
0
100
-100
200
-200
300
-300
h / mV
-100
-200
-300
400
-400
E1 > E0
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺
reaction coordinate
E2 > E0
E2 > E1
j / mA
300
200
j0 = 10-5 A
a = 0.5
100
0
-400
400
-300
300
-200
200
-100
100
100
-100
0
200
-200
300
-300
400
-400
h / mV
-100
-200
-300
E2 > E0
E2 > E1
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺
reaction coordinate
E3 > E0
E3 > E2
j / mA
300
200
j0 = 10-5 A
a = 0.5
100
-400
400
-300
300
-200
200
-100
100
0
0
100
-100
200
-200
300
-300
400
-400
h / mV
-100
-200
-300
E3 > E0
E3 > E2
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺
reaction coordinate
E4 > E0
E4 > E3
j / mA
300
200
10-5
j0 =
A
a = 0.5
100
-400
400
-300
300
-200
200
-100
100
0
0
100
-100
200
-200
300
-300
400
h / mV
-100
-200
-300
-400
E4 > E0
E4 > E3
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺
reaction coordinate
E5 > E0
E5 > E4
j / mA
300
200
j0 = 10-5 A
a = 0.5
100
-400
400
-300
300
-200
200
-100
100
0
0
100
-100
200
-200
300
-300
400
-400
h / mV
-100
-200
-300
E5 > E0
E5 > E4
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺
reaction coordinate
E6 > E0
E6 > E5
j / mA
300
200
j0 = 10-5 A
a = 0.5
100
-400
400
-300
300
-200
200
-100
100
0
0
100
-100
200
-200
300
-300
400
-400
h / mV
-100
-200
-300
E6 > E0
E6 > E5
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺
E7 < E0
reaction coordinate
j / mA
300
200
j0 = 10-5 A
a = 0.5
100
-400
400
-300
300
-200
200
-100
100
0
0
100
-100
200
-200
300
-300
400
-400
h / mV
-100
-200
-300
E7 < E0
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺
reaction coordinate
E8 < E0
E8 < E7
j / mA
300
200
j0 = 10-5 A
a = 0.5
100
-400
400
-300
300
-200
200
-100
100
0
0
-100
100
-200
200
-300
300
-400
400
h / mV
-100
-200
-300
E8 < E0
E8 < E7
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺
reaction coordinate
E9 < E0
E9 < E8
j / mA
300
200
j0 = 10-5 A
a = 0.5
100
-400
400
-300
300
-200
200
-100
100
0
0
-100
100
-200
200
-300
300
-400
400
h / mV
-100
-200
-300
E9 < E0
E9 < E8
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺
reaction coordinate
E10 < E0
E10 < E9
j / mA
300
200
j0 = 10-5 A
a = 0.5
100
-400
400
-300
300
-200
200
-100
100
0
0
-100
100
-200
200
-300
300
-400
400
h / mV
-100
-200
-300
E10 < E0
E10 < E9
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺
reaction coordinate
E11 < E0
E11 < E10
j / mA
300
200
j0 = 10-5 A
a = 0.5
100
400
-400
300
-300
200
-200
100
-100
0
0
-100
100
-200
200
-300
300
-400
400
h / mV
-100
-200
-300
E11 < E0
E11 < E10
F
𝐺c0
Ox + eRed
reaction coordinate
reaction coordinate
𝐺
reaction coordinate
E12 < E0
E12 < E11
j / mA
300
200
j0 = 10-5 A
a = 0.5
100
400
-400
300
-300
200
-200
100
-100
0
0
-100
100
-200
200
-300
300
-400
400
h / mV
-100
-200
-300
E12 < E0
E12 < E11