Proton relay in hydrogen-bond networks promotes alkaline hydrogen evolution electrocatalysis

Abstract

Common O-/H-down orientation of H₂O molecules on electrocatalysts brings favorable OH/H delivery however adverse H/OH delivery in their dissociation process, hampering H₂O dissociation kinetics of 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 metal and support (ΔΦ) induces a strong electric field at the metal-support interface that increases hydrogen-bond connectivity to promote proton relay, we examined this concept over cobalt phosphide-supported ruthenium (Ru/CoP) catalysts with a high ΔΦ = 0.4 eV, reaching record high HER performance with a Ru utilization activity of 66.1 A mg_Ru^-1 at a 100 mV overpotential.