Surface and Electronic-Structure Regulation of NiCrPt-LDH for Ampere-Level Methanol-Assisted Hydrogen Production in Alkaline Seawater

Substituting the anodic oxygen evolution reaction (OER) with the methanol oxidation reaction (MOR) provides an energy-saving route for alkaline seawater electrolysis, but it demands bifunctional electrodes that efficiently facilitate both anodic MOR and cathodic hydrogen evolution reactions (HER) in chloride-containing alkaline media. This work reports a surface and electronic-structure regulation strategy for a low-Pt (0.86 wt %) NiCrPt-LDH electrode constructed on nickel foam via a single-step hydrothermal route. The NiCrPt-LDH electrode integrates an open nanosheet framework, a defect-enriched metal-oxygen surface environment, and a super-hydrophilic/-aerophobic interface, which requires only 74, 146, and 228 mV to deliver 100, 500, and 1000 mA cm-2 for HER, respectively, with 1380 h of stability at 500 mA cm-2. Its Pt-mass-normalized HER activity is much higher than that of commercial Pt/C. For MOR in methanol-containing alkaline seawater, NiCrPt-LDH reaches 100 mA cm-2 under an applied potential of 1.401 V vs RHE. The NiCrPt-LDH (+) || NiCrPt-LDH (-) electrolyzer outputs 100 mA cm-2 at an operating voltage of 1.477 V, underscoring the potential of low-platinum, surface-engineered bifunctional LDH electrodes for methanol-assisted hydrogen production in alkaline seawater electrolysis.