Ti-doped NiFe-LDH nanosheets with tailored surface electronic structure for enhanced seawater splitting via lattice oxygen mechanism

A Ti 4+ -doped NiFe-LDH was employed as an electrocatalyst. • It requires overpotentials of 243 and 263 mV at 50 mA cm −2 in 1 M KOH and seawater. • Ti 4+ doping modulates the LDH electronic structure, activating the lattice oxygen mechanism. • This modulation significantly improves both electrocatalytic activity and long-term stability. The oxygen evolution reaction (OER) is kinetically sluggish and unstable, severely limiting its efficiency in water electrolysis, particularly in seawater. Here, we report the growth of Ti-doped NiFe layered double hydroxide (LDH) nanosheets on nickel foam (NF) via a one-step hydrothermal synthesis. The introduction of high-valent Ti 4+ cations effectively modulates the local electronic configuration of the NiFe-LDH host, thereby tending to promote the lattice oxygen mechanism (LOM) and fundamentally accelerate the OER kinetics. Consequently, the optimal Ti 0.1 NiFe-LDH/NF catalyst exhibits an overpotential of only 243 mV at 50 mA cm −2 in 1 M KOH, with a Tafel slope of 63.4 mV dec −1 . Importantly, it demonstrates exceptional operational durability, maintaining a current density of 50 mA cm −2 for more than 100 h with a minimal potential increase of just 7 mV. In alkaline seawater, the Ti-doped catalyst shows superior activity and corrosion resistance relative to its undoped counterpart, underscoring its potential for direct seawater electrolysis. This study elucidates the critical role of cation doping in activating the LOM pathway through optimization of the electronic configuration, and offers an effective strategy for developing high-performance and highly stable OER electrocatalysts for both freshwater and seawater splitting. Download: Download high-res image (251KB) Download: Download full-size image