Dual-functional engineering of Cr3+ doping in NiFeLDH: Achieving lattice stabilization and dynamic anti-corrosion shielding to synergistically promote alkaline seawater splitting

To address the challenges of the chlorine evolution reaction (CER) and catalyst corrosion in seawater electrolysis, this study developed a chromium-doped nickel-iron layered double hydroxide catalyst. This catalyst operates continuously for 100 h in alkaline seawater, showing consistent increases in activity. Chromium (Cr) doping strengthens the metal-oxygen (M-O) bond, inhibits the loss of lattice oxygen, and facilitates a shift toward the adsorbate evolution mechanism in the reaction pathway. Additionally, CrO 4 2- , produced by the in-situ oxidation and dissolution of Cr 3+ , establishes a dynamic “oxidation-dissolution-adsorption” equilibrium at the interface. This significantly reduces chloride ion (Cl - ) adsorption, corrosion, and the energy barriers of reactions. The introduction of a methanol-assisted system further decreases the overpotential. An electrolyzer that incorporates this system with Pt/C achieves efficient hydrogen production at a current density of 100 mA cm −2 and a voltage of 1.45 V.