Driving electrochemical organic hydrogenations on metal catalysts by tailoring hydrogen surface coverages

Electrochemical hydrogenation using renewable electricity holds promise as a sustainable approach to organic synthesis and the valorization of biomass-derived chemicals. Current strategies in the field usually employ alkaline conditions to suppress the competing hydrogen evolution reaction, and sourcing of hydrogen atoms for the hydrogenation is thus a challenge that can be addressed through local water dissociation on the electrode surface. Herein we demonstrate the computationally-guided design of electrochemical hydrogenation catalysts by tailoring their hydrogen coverage density and binding strength. Theoretical studies predict Cu, Au and Ag (with moderate H coverages) to be promising catalysts for electrochemical hydrogenation in alkaline media, which experiments confirm for a model organic substrate attaining yields and Faradaic efficiencies up to 90%. Furthermore, Cu, a non-precious metal electrocatalyst, is shown to promote the selective hydrogenation of a broad scope of unsaturated compounds featuring C=O, C=C, C≡C, and C≡N bonds with moderate to excellent conversions and chemoselectivities. Overall, this work demonstrates how the hydrogen coverage on the electrode surface can be tailored to design electrocatalysts based on non-precious metals for the hydrogenation of organic substrates. This knowledge is envisioned to guide the development of more efficient catalysts for organic hydrogenations as well as other chemical transformations of industrial interest.