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

Li, Yuefei; Zhang, Shishi; Li, Boyang; Su, Yaqiong; Kong, Jie; Li, Jiayuan · ACS Nano · 2025

basic_science · Level V

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Abstract

Common O-/H-down orientation of H<sub>2</sub>O molecules on electrocatalysts brings favorable OH/H delivery; however, adverse H/OH delivery in their dissociation process hampers the H<sub>2</sub>O dissociation kinetics of the alkaline hydrogen evolution reaction (HER). To overcome this challenge, we raised a synergetic H<sub>2</sub>O dissociation concept of metal-supported electrocatalysts involving efficient OH delivery from O-down H<sub>2</sub>O to the metal, timely proton relay from O-down H<sub>2</sub>O on the metal to H-down H<sub>2</sub>O on the support through the hydrogen-bond network, and prompt H delivery from H-down H<sub>2</sub>O 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 mg<sub>Ru</sub><sup>-1</sup> at -0.1 V vs RHE. The insights into this synergetic H<sub>2</sub>O dissociation mechanism provide opportunity for the design of bicomponent alkaline HER electrocatalysts.