Amorphous‐Crystalline Heterostructured Nanoporous High‐Entropy Alloys for High‐Efficiency pH‐Universal Water Splitting

Developing high-efficiency durable electrocatalysts in wide pH range for water splitting is significant for environmentally-friendly synthesis of renewable hydrogen energy. Herein, a facile method by dealloying designable multicomponent metallic glass precursors is reported to synthesize amorphous-crystalline heterostructured nanoporous high-entropy alloys (AC-HEAs) of CuAgAuPtPd, CuAgAuIrRu, and CuAgAuPtPdIrRu, heaped up by nanocrystalline particles with an average size of 2-3 nm and the amorphous glued phase. The synthesized AC-HEA-CuAgAuPtPd owns highly catalytic performances for hydrogen evolution reaction (HER), with 9.5 and 20 mV to reach 10 mA·cm^-2 in 0.5 m H₂SO₄ and 1.0 m KOH, and AC-HEA-CuAgAuIrRu delivers 208 and 200 mV for oxygen evolution reaction (OER). Moreover, a two-electrode electrolyzer made of the AC-HEA-CuAgAuIrRu bifunctional electrodes exhibit a low cell voltage of 1.48 and 1.49 V in the acidic and alkaline conditions at 10 mA·cm^-2 for overall water splitting. Combining the enhanced catalytic activities from nanoscale amorphous structure and atom-level synergistic catalyst in AC-HEAs provides an effective pathway for pH-universal electrocatalysts of water splitting.