Convex Cube-Shaped Pt 34 Fe 5 Ni 20 Cu 31 Mo 9 Ru High Entropy Alloy Catalysts toward High-Performance Multifunctional Electrocatalysis.

High entropy alloy (HEA) catalysts exhibit excellent multifunctional catalytic performance due to the synergistic effect of multi-metal components. However, shape-controlled synthesis of such kinds of HEA catalysts, especially those with high index facets, still faces great challenges, limiting further enhancement of their catalytic performance. Herein, one-pot synthesis of convex cube-shaped Pt 34 Fe 5 Ni 20 Cu 31 Mo 9 Ru HEA catalysts which possess rich (310) facets and a diagonal crystalline size of 38.5 nm is reported. Transmission electron microscopy measurements indicate cube-shaped nanocrystals are obtained first and further selective growth of pyramid on each facet of the cube-shaped nanocrystal results in a convex cube shape. Pt 34 Fe 5 Ni 20 Cu 31 Mo 9 Ru HEA catalysts show excellent electrocatalytic performance toward the oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), and oxygen evolution reaction (OER), which exhibit a half-wave potential of 0.87 V for ORR in 0.1 m HClO 4 , and overpotential of 20 and 259 mV for HER and OER at a current density of 10 mA cm -2 in an alkaline medium. A control experiment and density functional theory calculation indicate that the Ru element plays a decisive role in both the formation of the convex cube shape and also the high catalytic performance.