Strain Effect in Bimetallic Electrocatalysts in the Hydrogen Evolution Reaction

Unravelling the electrocatalytic activity origins of bimetallic nanomaterials is of great importance, yet fundamentally challenging. One of the main reasons for this is that the interactive contributions from geometric and electronic effects to enhancements in reaction activity are difficult to distinguish from one another. Here, on well-defined Ru-Pt core-shell (Ru@Pt) and homogeneous alloy (RuPt) model electrocatalysts, we are able to isolate these two effects. Furthermore, we observe the dominant role of strain in the intrinsic activity of the alkaline hydrogen evolution reaction. In the Ru@Pt icosahedral nanostructure, the highly strained Pt shells effectively accommodate the interfacial lattice mismatch from a facecentered cubic structured Ru core. This unique property leads to a weak binding of hydrogen and optimal interaction with hydroxyl species during the reaction, thus leading to an enhanced apparent activity of Ru@Pt.