Positive electrochemical potentials induce enhanced chemoselectivity and activity in the thermocatalytic hydrogenation of 3-nitrostyrene

Electrochemical promotion of catalysis is emerging as a powerful approach to control chemical reactions externally without complex catalyst modification, but this has mostly been used for substrates with a single reactive group so far. Herein, we demonstrate that this approach can induce full chemoselectivity in catalytic transformations of substrates with multiple functional groups. Specifically, we show that application of a positive electrochemical potential during the thermocatalytic hydrogenation of 3-nitrostyrene exclusively delivered one single product, 1-ethyl-3-nitrobenzene, with six-fold enhanced yield, while a complex product mixture was obtained at open circuit voltage. These effects resulted from the combined effects of a positive electrode polarization and acidification of the bulk solution through a concurrent hydrogen oxidation reaction. Surface-enhanced infrared absorption spectroscopy and kinetic experiments showed that the positive polarization optimized surface concentrations of reactants and the orientation of adsorbed 3-nitrostyrene. Validation with additional reactants and catalyst implies a broader relevance of our findings.