Electrochemical Dealloying of PdCu3 Nanoparticles to Achieve Pt‐like Activity for the Hydrogen Evolution Reaction

Manipulating the d‐band center of the metal surface and hence optimizing the free energy of hydrogen adsorption (ΔGH) close to the optimal adsorption energy (ΔGH=0) for hydrogen evolution reaction (HER), is an efficient strategy to enhance the activity for HER. Herein, we report a oleylamine‐mediated (acting as the solvent, stabilizer, and reducing agent) strategy to synthesize intermetallic PdCu3 nanoparticles (NPs) without using any external reducing agent. Upon electrochemical cycling, PdCu3 transforms into Pd‐rich PdCu (ΔGH=0.05 eV), exhibiting remarkably enhanced activity (with a current density of 25 mA cm−2 at ∼69 mV overpotential) as an alternative to Pt for HER. The first‐principle calculation suggests that formation of low coordination number Pd active sites alters the d‐band center and hence optimal adsorption of hydrogen, leading to enhanced activity. This finding may provide guidelines towards the design and development of Pt‐free highly active and robust electrocatalysts.