Proton Relay in Hydrogen-Bond Networks Promotes Alkaline Hydrogen Evolution Electrocatalysis

Common O-/H-down orientation of H2O molecules on electrocatalysts brings favorable OH/H delivery; however, adverse H/OH delivery in their dissociation process hampers the H2O dissociation kinetics of the alkaline hydrogen evolution reaction (HER). To overcome this challenge, we raised a synergetic H2O dissociation concept of metal-supported electrocatalysts involving efficient OH delivery from O-down H2O to the metal, timely proton relay from O-down H2O on the metal to H-down H2O on the support through the hydrogen-bond network, and prompt H delivery from H-down H2O to the support. After theoretically profiling that a high work function difference between the metal and the support (ΔΦ) induces a strong electric field at the metal–support interface that increases hydrogen-bond connectivity to promote proton relay, we practiced this concept over cobalt phosphide-supported ruthenium (Ru/CoP) catalysts with a high ΔΦ = 0.4 eV, achieving a record-high Ru utilization HER activity of 66.1 A mgRu–1 at −0.1 V vs RHE. The insights into this synergetic H2O dissociation mechanism provide opportunity for the design of bicomponent alkaline HER electrocatalysts.