Terephthalic Acid Intercalation Strengthens NiFe-Layered Double Hydroxide for Durable and Efficient Seawater Electrolysis

Abstract

Developing oxygen evolution catalysts that couple high activity with robust corrosion resistance is essential for sustainable hydrogen production from seawater. Here, we report a molecular intercalation strategy to stabilize nickel–iron layered double hydroxides (NiFe-LDHs) by incorporating terephthalic acid (TPA) via a one-step electrodeposition route. The resulting NiFe-LDH(TPA) features a nanoflower morphology with enlarged interlayer spacing and strong C–O–Fe coordination, which jointly optimize electronic structure and suppress metal dissolution. Consequently, NiFe-LDH(TPA) requires only 216 mV to deliver 10 mA cm-2 with a Tafel slope of 59 mV dec-1 in 1 M KOH seawater, outperforming RuO2. Remarkably, the catalyst maintains activity for over 700 h at 500 mA cm-2 with negligible degradation. Operando Raman spectroscopy reveals that TPA intercalation facilitates the Ni2+/Ni3+ transition toward active NiOOH species at lower potentials while mitigating Cl--induced corrosion. This work introduces organic molecular intercalation as an effective route to engineer robust LDH-based anodes for direct seawater electrolysis.