Interfacial Electron Transfer-Driven Activity Enhancements of Carbide/Alloy Heterostructured Catalysts toward Water Electrolysis for High-Performance Anion Exchange Membrane Water Electrolysis

Abstract

Designing highly efficient and durable electrocatalysts remains a key challenge for practical alkaline water electrolysis. Here, rationally designed carbide/alloy heterostructured catalysts, Mo ₂ C/NiMo for hydrogen evolution reaction (HER) and Mo ₂ C/FeNiMo for oxygen evolution reaction (OER), were developed for activity enhancement driven by interfacial electron transfer to enable anion exchange membrane water electrolysis (AEMWE) of extraordinary performances. Mo ₂ C/NiMo and Mo ₂ C/FeNiMo achieved ultralow overpotentials of 169 and 303 mV, respectively at 500 mA cm ^-2 . The Mo ₂ C//NiMo@NF//PiperION//Mo ₂ C//FeNiMo@NF based AEMWE delivered an exceptionally high current density of 2.645 A cm ^-2 at 2.0 V, along with an insignificant 2.0 % decay after 50 h of operation at a commercially relevant current density of 0.5 A cm ^-2 , underscoring its outstanding catalytic efficiency and durability. In the two carbide/alloy heterostructured catalysts, electron flows from the alloy domain to the carbide domain, triggering the interfacial synergy. The interfacial synergy promotes efficient coupling of water dissociation and H₂ desorption along the Volmer-Heyrovsky route to boost HER activities of Mo ₂ C/NiMo, and creates more electropositive Fe and Ni for favorable formation of active high-valent intermediates to realize high OER activities of Mo ₂ C/FeNiMo. This work highlights the great promise of carbide/alloy heterostructures as advanced electrocatalysts for scalable and efficient alkaline water electrolysis.