Electronic Modulation-Driven Dual Self-Reconstruction of a Nickel–Molybdenum Oxide Catalyst for Durable and Highly Efficient Anion-Exchange-Membrane Water Electrolysis

Abstract Surface reconstruction of precatalysts during water splitting governs the formation of active catalysts, yet engineering robust dual-functional precatalysts that self-reconstruct into stable, distinct active phases under different hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) conditions remains challenging. Here, we tailor the in situ reconstruction of a self-supported nickel–molybdenum oxide precatalyst through the incorporation of iron and vanadium to control the formation of HER- and OER-stable active phases for efficient anion-exchange-membrane water electrolysis (AEMWE). In 1.0 M KOH, the as-prepared NiFeVMo requires overpotentials of only 25 and 207 mV to reach 10 mA cm–2 for HER and OER, respectively, while demonstrating stable operation throughout the durability tests conducted for approximately 302 and 192 h at 100 mA cm–2 for HER and OER, respectively. In an AEM water electrolyzer operating at 80 °C, dual-functional NiFeVMo used as both an anode and cathode achieves a current density of 1.0 and 4.0 A cm–2 at uncorrected cell voltages of 1.649 and 1.967 V, respectively. Combined experimental characterization and density functional theory calculations reveal cooperative electronic and structural effects arising from this multimetal material that lower reaction energetics, improve charge transfer, and stabilize the activated catalyst. This work provides a strategy for designing a PGM-free self-reconstructing precatalyst with dual catalytic activity, offering a promising approach for the development of earth-abundant and highly efficient catalysts for electrochemical energy conversion and storage technologies.