Galvanic-displacement-derived CuO_x-Pt/Cu interfaces for operando activation and enhanced HER in acidic media

This work presents an interesting and easy galvanic displacement strategy for the synthesis of self-supported Pt-Cu heterointerfaces optimized for the hydrogen evolution reaction (HER) in acidic media. By galvanically replacing surface copper with Pt²⁺ ions, we achieve a unique CuO_x-Pt/Cu interface, which undergoes dynamic in situ activation during the HER to form a Pt-Cu₂O/Cu heterostructure, in which Pt is present in trace amounts. This transformation significantly enhanced the electrocatalytic HER requiring just 38 mV and 76 mV as overpotentials for 10 and 100 mA cm^-2, respectively, outperforming bulk Pt foil. The synergistic interplay between Pt, Cu₂O, and Cu is believed to have delivered superior charge transfer and active-site stabilization, while the self-supporting architecture improves catalyst durability and accessibility. Our approach demonstrates scalable, cost-efficient catalyst fabrication that maximizes Pt utilization while minimizing Pt consumption, providing a promising pathway toward next-generation HER electrocatalysts for efficient green hydrogen production under acidic conditions with ultralow Pt content.