Driving Electrochemical Organic Hydrogenations on Metal Catalysts by Tailoring Hydrogen Surface Coverages

Electrochemical hydrogenation, powered by renewable electricity, represents a promising sustainable approach for organic synthesis and the valorization of biomass-derived chemicals. Traditional strategies often rely on alkaline conditions to mitigate the competing hydrogen evolution reaction, posing challenges in sourcing hydrogen atoms for hydrogenation, which can be addressed through localized water dissociation on the electrode surface. In this study, we present a computationally guided design of electrochemical hydrogenation catalysts by optimizing hydrogen coverage density and binding strength on the electrode. Our theoretical investigations identify Cu, Au, and Ag - metals with moderate hydrogen coverage - as promising catalysts for electrochemical hydrogenations in alkaline media. These predictions are experimentally validated using a model organic substrate (acetophenone), achieving yields and faradaic efficiencies of up to 90%. Additionally, Cu, a nonprecious metal, is demonstrated to selectively hydrogenate a wide range of unsaturated compounds, including C═O, C═C, C≡C, and C≡N bonds, at low potentials with moderate to excellent conversion rates and chemoselectivities. This work highlights the potential of tailoring hydrogen coverage on electrode surfaces to rationally design nonprecious metal electrocatalysts for efficient organic hydrogenations. The insights gained here are expected to inform the development of more effective catalysts for organic hydrogenations and other industrially relevant chemical transformations.