Electron-Rich Platinum Atoms in Lattice of Nickel-Iron Layered Double Hydroxide Enhance Seawater Electrolysis

Electrocatalytic hydrogen (H₂) evolution reaction (HER) in seawater is among the most attractive ways to produce H₂, but its efficiency is still far below commercialization need. Herein, platinum (Pt) atoms are doped in lattice of nickel-iron layered double hydroxide (NiFe-LDH) to form a PtNiFe-D15 catalyst with 0.98 wt.% Pt. In HER in alkaline seawater, overpotential to drive industrial-level current density of 1000 mA cm^-2 on PtNiFe-D15 is 217 mV, which is much lower than those on commercialized 20 wt.% Pt/carbon catalyst (489 mV) and catalysts reported widely. Moreover, PtNiFe-D15 has faster kinetics and better stability. Doping Pt atoms in NiFe-LDH lattice forms Ni atoms with empty electronic orbitals and electron-rich Pt atoms benefit for water splitting, hydroxyl desorption and H₂ desorption. This enhances seawater-based HER efficiency on PtNiFe-D15. PtNiFe-D15 is also used as cathode to form an anion exchange membrane water electrolyzer (AEMWE). In alkaline seawater electrolysis, the AEMWE shows a superior stability, with the potential to drive 1000 mA cm^-2 being 1.75 V, which is lower than those in systems reported widely. This provides a great potential for commercialization.