Ir-Doped Pd Nanosheet Assemblies as Bifunctional Electrocatalysts for Advanced Hydrogen Evolution Reaction and Liquid...

Although great progress in pursuing high-performance catalysts for advanced electrocatalysis has been made, the design of high-efficiency electrocatalysts continues to be a huge challenge for commercializing electrochemical energy technologies. Herein, a three-dimensional (3D) hierarchical assembly nanostructure consisting of ultrathin Ir-doped Pd nanosheets has been well designed, which could serve as a bifunctional electrocatalyst for advanced hydrogen evolution reaction (HER) and liquid fuel electrooxidation. In particular, the optimized Pd_83.5Ir_16.5 nanocatalyst displays excellent electrocatalytic HER performance with an overpotential of only 73 mV at 10 mA cm^-2 along with excellent stability. More importantly, it can also show outstanding electrocatalytic performance for liquid fuel oxidation with a mass activity of 4326.1 mA mg_metal^-1 for ethylene glycol oxidation reaction. Mechanistic study reveals that the highly porous 3D nanostructure, the modulation of electronic structure after the introduction of Ir, not only guarantees a high level of exposure of surface active sites and smooth charge transfer but also generates the new active centers for facilitating the adsorption of H₂O and recombination of H*, thereby dramatically increasing the intrinsic activity of electrocatalysis.