Designing Pt-based electrocatalysts with high surface energy

The reactivity of an electrocatalyst depends strongly on its surface structure. Pt-based electrocatalysts of nanocrystals (NCs) enclosed with high-index facets contain a large density of catalytically active sites formed from step and kink atoms on the facets and exhibit intrinsically superior activity. However, the Pt-based NCs of high-index facets do possess a high surface energy and are thermodynamically metastable, leading to a big challenge in their shape-controlled synthesis. To overcome the challenge, kinetic–thermodynamic control of crystal growth is indispensable and is currently realized mainly by electrochemical methods and surfactant-based wet chemical approaches. This Perspective reviews recent progresses in Pt-based electrocatalysts of monometallic and bimetallic NCs of high surface energy with different morphologies of convex or concave tetrahexahedron, trapezohedron, trisoctahedron, hexoctahedron, etc. Remarkable electrocatalytic performance of these NCs has been demonstrated. Despite the considerable progress already made, the electrocatalysts of NCs with high surface energy still hold significant future opportunities in both fundamental understanding and practical applications