Title: Interfacial structure of water as a new descriptor of hydrogen evolution reaction

Authors: Lin-fan Shen  Bang-an Lu  Yu-yang Li  Jia Liu  Zhi-chao Huang-fu  Hao Peng  Jin-yu Ye  Xi-ming Qu Jun-ming Zhang  Guang Li  Wen-bin Cai  Yan-Xia Jiang  Shi-gang Sun

Abstract: Driven by the persisting poor understanding of the sluggish kinetics of the hydrogen evolution reaction (HER) on Pt in alkaline media, a direct correlation of the interfacial water structure and activity is still yet to be established. Here, we first demonstrated a strong dependence of the proton donor structure on the HER activity and pH. The structure of the first layer evolutes from the proton acceptors to the donors with increasing pH. In the base, the reactivity of the interfacial water varied with their structure, and the activation energies of water dissociation increased in the sequence: the dangling O–H bonds < the trihedrally coordinated water < the tetrahedrally coordinated water. Moreover, optimizing the adsorption of H and OH intermediate can re‐orient the interfacial water molecules with their H atoms pointing towards the electrode surface, thereby enhancing the kinetics of HER. Our results clarified the dynamic role of the water structure at the electrode‐electrolyte interface during HER and the design of highly efficient HER catalysts.

Full-Link: https://onlinelibrary.wiley.com/doi/10.1002/anie.202007567