Tensile‐Strained Holey Pd Metallene toward Efficient and Stable Electrocatalysis

Abstract Noble metal‐based metallenes are attracting intensive attention in energy catalysis, but it is still very challenging to precisely control the surface structures of metallenes for higher catalytic properties on account of their intrinsic thermodynamic instability. Herein, the synthesis of tensile‐strained holey Pd metallene by oxidative etching is reported using hydrogen peroxide, which exhibits highly enhanced catalytic activity and stability in comparison with normal Pd metallene toward both oxygen reduction reaction and formic acid oxidation. The pre‐prepared Pd metallene functions as a catalyst to decompose hydrogen peroxide, and the Pd atoms in amorphous regions of Pd metallene are preferentially removed by the introduced hydrogen peroxide during the etching process. The greatly enhanced ORR activity is mainly determined by the strong electrostatic repulsion between intermediate O * and the dopant O, which balances the adsorption strength of O * on Pd sites, ultimately endowing a weakened adsorption energy of O * on TH‐Pd metallene. This work creates a facile and economical strategy to precisely shape metallene‐based nanoarchitectures with broad applications for energy systems and sensing devices.