Nitrate intercalation suppresses Fe active-site dissolution in NiFe-LDH for durable industrial alkaline oxygen evolution

The practical deployment of alkaline water electrolysis (AWE) is fundamentally limited by the instability of oxygen evolution reaction (OER) catalysts caused by continuous dissolution of active metal sites under harsh operating conditions. Herein, we report a strategy for stabilizing NiFe layered double hydroxides (NiFe-LDH) via weak Brönsted base intercalation, which tunes the interlayer spacing and interfacial electronic structure. Through the intercalation of weakly basic nitrate anions (NO 3 − ), a nitrate-modified NiFe-LDH (NiFe-NO 3 ) is constructed, which effectively suppresses Fe dissolution by stabilizing high-valence Ni/Fe species during operation. As a result, NiFe-NO 3 exhibits exceptional durability, maintaining stable operation at 1000 mA cm −2 in 30 wt% KOH at 80 °C for over 500 h with an ultralow degradation rate of 0.04 mV·h −1 (retention rate of electrochemical activity was 99.1%), representing a ∼12-fold lifetime improvement over pristine NiFe-LDH. Mechanistic studies reveal that NO 3 − intercalation induces synergistic effects including slight interlayer expansion, electronic redistribution, and regulation of interlayer Brönsted basicity, which collectively stabilize high-valence Ni/Fe species and preserve the oxyhydroxide active phase during OER. This work demonstrates that Brönsted base intercalation provides an effective strategy to suppress active-site dissolution and offers new insights for the design of durable OER catalysts for industrial alkaline water electrolysis (AWE).