Lattice Strain-Induced Regulation of Interfacial Water Promotes Hydrogen Production from Natural Seawater

Natural seawater electrolysis provides an effective approach to harnessing abundant ocean reserves for hydrogen production. However, its industrial application is hindered by low efficiency and limited durability due to electrocatalyst deactivation or electrolyzer blockage initiated by precipitation at the cathode and chloride corrosion at the anode. Here, we report a strain-engineered strategy that simultaneously suppresses precipitation and chloride corrosion and enables bipolar hydrogen production in natural seawater electrolysis. A Cu_3–xCo_xP catalyst with lattice compressive strain is developed to boost hydrogen evolution reaction (HER) by modulating interfacial water behavior and enhancing catalyst surface hydrophilicity, thereby accelerating water dissociation and facilitating bubble release. This process disrupts the local pH gradient and suppresses precipitation formation over the catalyst. We evidence that this catalyst exhibits high stability, operating for over 1000 h at 100 mA cm^–2 in natural seawater. Furthermore, this catalyst can drive formaldehyde oxidation reaction (FOR) at the anode that not only yields value-added formate but also produces H₂ with a low voltage input. When integrated into an electrolyzer, it enables simultaneous hydrogen production at both the cathode and anode, operating at a low cell voltage of 0.55 V at 100 mA cm^–2 for over 300 h without chloride hazards.