A Nickel Phosphine Complex as a Fast and Efficient Hydrogen Production Catalyst

Here we report the electrocatalytic reduction of protons to hydrogen by a novel S2P2 coordinated nickel complex, [Ni(bdt)(dppf)] (bdt = 1,2-benzenedithiolate, dppf = 1,1'-bis(diphenylphosphino)ferrocene). The catalysis is fast and efficient with a turnover frequency of 1240 s(-1) and an overpotential of only 265 mV for half activity at low acid concentrations. Furthermore, catalysis is possible using a weak acid, and the complex is stable for at least 4 h in acidic solution. Calculations of the system carried out at the density functional level of theory (DFT) are consistent with a mechanism for catalysis in which both protonations take place at the nickel center.