The electrocatalytic reduction of protons to H2 by [Ni(P Ph2NC6H4-hex2)2](BF 4)2 (where PPh2N C6H4-hex2 = 1,5-di(4-n-hexylphenyl)-3,7-diphenyl-1,5- diaza-3,7-diphosphacyclooctane) in the highly acidic ionic liquid dibutylformamidium bis(trifluoromethanesulfonyl)amide shows a strong dependence on added water. A turnover frequency of 43,000-53,000 s-1 has been measured for hydrogen production at 25°C when the mole fraction of water (χH2O) is 0.72. The same catalyst in acetonitrile with added dimethylformamidium trifluoromethanesulfonate and water has a turnover frequency of 720 s-1. Thus, the use of an ionic liquid/aqueous solution enhances the observed catalytic rate by more than a factor of 50, compared to a similar acid in a traditional organic solvent. Complexes [Ni(PPh 2NC6H4X2)2](BF4) 2 (X = H, OMe,CH2P(O)(OEt)2, Br) are also catalysts in the ionic liquid/water mixture, and the observed catalytic rates correlate with the hydrophobicity of X.
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - Sep 25 2012|
- Proton relay
- Renewable energy
ASJC Scopus subject areas