Metal surfaces catalyze polarization-dependent hydride transfer from H2

Hydride transfer is a critical elementary reaction step that spans biological catalysis, organic synthesis, and energy conversion. Conventionally, hydride transfer reactions are carried out using (bio)molecular hydride reagents under homogeneous conditions. Herein, we report a conceptually distinct heterogeneous hydride transfer reaction via the net electrocatalytic hydrogen reduction reaction (HRR) which reduces H2 to hydrides. The reaction proceeds by H2 dissociative adsorption on a metal electrode to form surface M−H species, which are then negatively polarized to drive hydride transfer to molecular hydride acceptors with up to 95% Faradaic efficiency. We find that the hydride transfer reactivity of surface M−H species is highly tunable and its thermochemistry depends on the applied potential in a Nernstian fashion. Thus, depending on the electrode potential, we observe that the thermodynamic hydricity of Pt−H on the same Pt electrode can span a range of >40 kcal mol−1. This work highlights the critical role of electrical polarization on heterogeneous hydride transfer reactivity and establishes a strategy for accessing reactive hydrides directly from H2.