Ni3Se2@NiFe Layered Double Hydroxides for Durable Seawater Electrolysis

Abstract Developing durable bifunctional electrocatalysts is very crucial for efficient electrochemical water splitting. However, the sluggish reaction kinetics and interface instability restrict their practical application. Herein, we report a hierarchical Ni3Se2@NiFe-LDH heterostructure fabricated via a sequential seed-assisted hydrothermal strategy to ensure strong interfacial adhesion. The metallic Ni3Se2 nanowires serve as a conductive skeleton to facilitate electron transport, while the dense NiFe-LDH shell exposes abundant active sites. In 1.0 M KOH solution, the optimized electrode presents the overpotentials of 78 mV at 10 mA cm–2 for HER and 224 mV at 50 mA cm–2 for OER. Additionally, the assembled electrolyzer requires a cell voltage of 1.69 V at 50 mA cm–2. In alkaline seawater, the electrode requires overpotentials of 117 mV for HER and 273 mV for OER at 10 and 50 mA cm–2, respectively. Remarkably, the composites present robust stability after 150 h of operation in alkaline seawater, demonstrating their viability as electrocatalysts for overall seawater splitting.