Metal‐Free Dihydrogen Oxidation by a Borenium Cation: A Combined Electrochemical/Frustrated Lewis Pair Approach

In order to use H 2 as a clean source of electricity, prohibitively rare and expensive precious metal electrocatalysts, such as Pt, are often used to overcome the large oxidative voltage required to convert H 2 into 2 H + and 2 e − . Herein, we report a metal‐free approach to catalyze the oxidation of H 2 by combining the ability of frustrated Lewis pairs (FLPs) to heterolytically cleave H 2 with the in situ electrochemical oxidation of the resulting borohydride. The use of the NHC‐stabilized borenium cation [(I i Pr 2 )(BC 8 H 14 )] + (I i Pr 2 =C 3 H 2 (N i Pr) 2 , NHC=N‐heterocyclic carbene) as the Lewis acidic component of the FLP is shown to decrease the voltage required for H 2 oxidation by 910 mV at inexpensive carbon electrodes, a significant energy saving equivalent to 175.6 kJ mol −1 . The NHC–borenium Lewis acid also offers improved catalyst recyclability and chemical stability compared to B(C 6 F 5 ) 3 , the paradigm Lewis acid originally used to pioneer our combined electrochemical/frustrated Lewis pair approach.