Catalyst for Industrial‐Scale Seawater Electrolysis: Inhibit Active Metal Dissolution and Chlorine Corrosion

Alkaline seawater electrolysis is a promising technology for sustainable green hydrogen production. However, active metal dissolution and chlorine-induced corrosion during long-term, industrial-scale operation pose critical challenges to catalyst stability. Here, a surface engineering strategy is reported using phytic acid (PA) as a molecular "armor" to construct highly durable oxygen evolution reaction (OER) catalysts. Comprehensive characterization and density functional theory (DFT) calculations reveal that surface modification with PO₄ ^3- groups not only facilitates surface reconstruction to form NiOOH active sites, but also optimizes the adsorption-desorption dynamics of key reaction intermediates, thereby enhancing catalytic performance. Importantly, the PO₄ ^3- layer suppresses the adsorption of chloride ions at active sites, significantly improving corrosion resistance under harsh seawater conditions. As a result, the catalyst delivers a current density of 100 mA cm^-2 at a low overpotential of 208 mV in alkaline seawater, maintaining stable performance over 1500 h. When integrated as the anode in a proton exchange membrane electrolyzer, it supports operation at 1 A cm^-2 with a cell voltage of only 2.18 V, exhibiting no performance degradation over 500 h.