Reconstructing Short‐Hydrogen‐Bond Network via Hexametaphosphate Boosts Chloride‐Ion Shielding Effect Enhancement in Seawater Electrolysis

Abstract The bottleneck for direct seawater splitting is the highly selective and durable oxygen evolution reaction (OER) electrocatalyst, primarily due to side reactions caused by chloride ions (Cl ⁻ ). Therefore, this study proposes a promising strategy by coupling hydrophilic units to the catalyst‐electrolyte interface to reconstruct connected hydrogen‐bond networks, thereby enhancing OER activity in seawater systems. Herein, this study finds that the hydrogen‐bond interactions between hexametaphosphate (HMP) and H ₂ O molecules not only direct the reconstruction short‐hydrogen‐bond network to the NiFe‐LDH (NFL) surface but also serve as a channel to inhibit chloride ions and promote the dehydrogenation process. Through electrochemical performance tests, it exhibits excellent chlorine resistance and stability. Compared with NFL (with a chlorine resistance stability coefficient of 14.3), HMP‐NFL has a chlorine resistance stability coefficient of only 7.49, which owned superior chlorine resistance properties. More importantly, it operates stably at 1.8 V vs RHE for over 1000 h under 1 M NaOH + seawater, far surpassing the performance of NFL without short‐range hydrogen‐bond construction, which deteriorates within 200 h of operation. The design of short‐range hydrogen bond networks paves the way for the design of efficient seawater electrolysis.