In Situ Formation of Multi-Principal Element Oxide on a Bulk Nanoporous Intermetallic Alloy for Ultra-Efficient Hydrogen Production at Ampere-Level Current Density.

Developing highly efficient and durable electrocatalysts for hydrogen production via water splitting remains a pivotal challenge for sustainable energy. In this work, we present a bulk nanoporous C15 intermetallic alloy synthesized through electrodealloying of a eutectic multiprincipal element precursor. Unlike conventional metallic nanostructures, this catalyst features an ultrathin multiprincipal element oxide (MPEO) layer, which generates abundant active sites and achieves exceptional hydrogen evolution reaction (HER) activity, surpassing most reported catalysts. Crucially, the material demonstrates unprecedented stability at industrial-level current densities (1 A/cm at 396 mV), enabled by operando amorphization of the MPEO layer during prolonged operation. This structural evolution stabilizes the catalyst-electrolyte interface while retaining intrinsic activity. Our findings redefine design principles for robust, high-performance electrocatalysts by integrating bulk intermetallic architectures with self-optimizing surface chemistry.