| Fe Mechanisms | Medium | Reaction |
| Mechanism # 1 (pH 2) | Anode | 2Fe(s) - 4e˚ → 2Fe2+(aq) (E˚ = +0.447 V) (1’) 2H2O(l) - 4e˚ → O2(g) + 4H+(aq) (E˚ = −1.229 V) (2’) |
| Solution | 2Fe2+(aq) + 4OH˚(aq) → 2Fe(OH)2(s) (3’) | |
| Cathode | 8H+(aq) + 8e˚ → 4H2(g) (E˚ = 0.000 V) (4’) | |
| Total | 2Fe(s) + 6H2O(l) → O2(g) + 4H2(g) + 2Fe(OH)2(s) (5’) | |
| Mechanism # 2 (pH 7) | Anode | 2Fe(s) - 4e˚ → 2Fe2+(aq) (E˚ = +0.447 V) (1’) Fe2+(aq) - e˚ → Fe3+(aq) (E˚ = −0.771 V) (6’) Fe(s) - 3e˚ → Fe3+(aq) (E˚ = +0.037 V) (7’) |
| Solution | 2Fe2+(aq) + 4OH˚(aq) → 2Fe(OH)2(s) (3’) 2Fe3+(aq) + 6OH˚(aq) → 2Fe(OH)3(s) (8’) | |
| Cathode | 8H2O(l) + 8e˚ → 4H2(g) + 8OH˚(aq) (E˚ = −0.828 V) (9’) | |
| Total | 3Fe(s) + 8H2O(l) → Fe(OH)2(s) + 2Fe(OH)3(s) + 4H2(g) (10’) | |
| Mechanism # 3 (pH 12) | Anode | Fe(s) - 3e˚ → Fe3+(aq) (E˚ = +0.037 V) (7’) |
| Solution | 2Fe3+(aq) + 6OH˚(aq) → 2Fe(OH)3(s) (8’) | |
| Cathode | 8H2O(l) + 8e˚ → 4H2(g) + 8OH˚(aq) (E˚ = −0.828 V) (9’) | |
| Total | 2Fe(s) + 6H2O(l) →2Fe(OH)3(s) + 3H2(g) (11’) | |
| Al Mechanism (pH 7) | Anode | Al(s) - 3e˚ →Al3+(aq) (E˚ = +1.660 V) (12’) 2H2O(l) - 4e˚ → O2(g) + 4H+(aq) (E˚ = −1.229 V) (2’) |
| Solution | Al3+(aq) + 3OH˚(aq) → Al(OH)3(s) (13’) Al(OH)˚4(aq) → OH˚(aq) + Al(OH)3(s) (14’) | |
| Cathode | 8H2O(l) + 8e˚ → 4H2(g) + 8OH˚(aq) (E˚ = −0.828 V) (9’) Al(s) + 4OH˚(aq) ? 3e˚ → Al(OH)˚4(aq) (15’) | |
| Total | 2Al(s) + 8H2O → O2(g) + 5H2(g) + 2Al(OH)3(s) (16’) |