Table 3. Properties of catalysts based on small peptide sequences for catalytic production of H2 from aqueous solution a .
| Catalyst center | Peptide host | Electron supply/conditions (overpotential) | TON b | TOF b (s–1) | Ref. |
| [(μ-S2)Fe2(CO)6] | 8 | [Ru(bpy)(tpy)]2+, c 0.1 M NaAsc/Tris–HCl, pH 8.5 | 9 (2 h) | 0.003 (ini) | 145 |
| [(μ-(S–CH2 CHRCH2–S))Fe2(CO)6] | 9 | 15 eq. PS, 0.05 M NaAsc/citrate buffer, pH 4.5 | 84 (2.3 h) | — | 147 |
| [μ-(pdt) Fe2(CO)5] | Val–Ppa–Leu 11 | EC (CV)/GC electrode, CH3CN : H2O (3 : 1) acid acetic (750 mV) | — | — | 149 |
| 15 | 15 | EC (CV)/GC electrode, 348 K, 1 atm (N2), H2O, pH 6 | — | 21 ± 5% | 156 |
| [Ni(PPh2NAPPA-WR10)2]2+ | WR10 16 | EC (CV)/GC electrode, CH3CN : H2O (90 : 10) acidic DMF (540 mV) | — | 106 000 | 159 |
| 20 | Gly–Gly–His 20 | EC (CPE)/Hg pool electrode, MOPS, pH 8, 1 M NaCl (600 mV) | 275 (2.5 h) | 0.031 (2.5 h) | 161 |
| 21 | MP11-Ac 21 | EC (CPE)/Hg pool electrode, KPi, pH 7 (852 mV) | 25 000 (4 h) | 6.7 (10 m) | 162 |
| 22 | Ht c-552 (Met61Ala) mutant) 22 | EC (CPE)/Hg pool electrode, KPi, pH 7 (830 mV) | 11 000 (6 h) | — | 129 |
aEC = electrochemistry, CV = cyclic voltammetry, CPE = constant potential electrolysis, GC = glassy carbon, ini = initial, Ppa = N-Boc-3-(diphenylphosphorothioyl)alanine.
bIn parentheses is the duration of the experiment used to determine the corresponding value.
cDirectly coordinated by the His10.