Tailoring acidic microenvironment for enhanced electrocatalytic hydrogen generation from alkaline seawater

Alkaline seawater electrolysis for hydrogen production powered by clean energy is increasingly driving the development of a low-carbon economy. However, the limited proton availability in the electrolyte leads to sluggish cathodic reaction kinetics and elevates energy consumption, which hinders its large-scale application. Herein, low Pt loaded NiCo phosphate-coated NiCoP nanoneedle arrays on Ni foam (Pt@NCPi@NCP/NF) using a spontaneous redox strategy is developed for efficient and durable electrocatalytic hydrogen production from alkaline seawater. <em>In situ</em> Raman spectroscopy confirms that a large number of hydrated hydrogen ion intermediates are generated on the surface of Pt@NCPi@NCP/NF during the hydrogen evolution reaction (HER) process, which successfully constructs a localized acidic microenvironment. Concurrently, the surface Pi layer functions as a proton buffer layer, effectively regulating proton supply to enhance the utilization efficiency of active sites. As a result, the catalyst exhibits excellent HER kinetics under alkaline conditions with a Tafel slope of only 39.65 mV·dec^–1 and a low overpotential of 136 mV to reach 1000 mA·cm^–2.