Surface Strain Effect on Electrocatalytic Hydrogen Evolution Reaction of Pt-Based Intermetallics

Elucidating the relationship between electrocatalytic activity and surface strain is pivotal for designing highly efficient electrocatalysts for the acidic hydrogen evolution reaction (HER). However, a general correlation is currently absent due to the lack of ideal catalytic materials platforms with well-defined structures and components. Herein, we select L1(0) and L1(2) Pt-based intermetallic compounds as model materials to construct a series of core-shell catalysts with strained Pt skins (IMC@Pt) and establish the correlation between surface strain and HER performance. Density functional theory calculations were performed to determine the surface strain degree, d-band center, and key descriptor Delta G(H*) of the catalysts for HER. By combining theoretical and experimental data, we propose a volcano-type trend between surface strain and the HER activity of IMC@Pt with an apex at 4% compressive strain. In addition, we demonstrate a class of highly active and durable IMC@Pt catalysts for acidic HER. Among them, the Pt3V@Pt catalyst exhibits the highest intrinsic HER activity with a specific activity of 4.24 mA cm(Pt)(-2) at an overpotential of 20 mV, which is 4 times higher than that of Pt. This work provides a solid understanding of the essential nature of PtM alloy catalysts and can guide the design of high-performance HER catalysts for water electrolyzers.