Durable Seawater Electrolysis Enabled by Spherical Electrostatic Repulsion and Catalyst-Support Interaction

The electrolysis of seawater driven by renewable energy for hydrogen production represents a promising strategy toward net-zero emissions. The high concentration of chloride ions (Cl^-) in seawater not only competes with the oxygen evolution reaction (OER) at the anode but also causes corrosion of the catalyst material. The construction of electrostatic shielding via anions on the catalyst surface can repel Cl^-. However, studies on regulating anion distribution through designed geometries to maximize such repulsion remain limited. Herein, a sphere-like catalyst, constructed with a heterojunction of carbonate-intercalated nickel-iron layered double hydroxides in situ grown on malachite microspheres (MM), exhibits enhanced catalytic durability and activity. The spherical electrostatic field induced by carbonate anions protects the catalyst, and the catalyst-support interaction (CSI) tunes the electronic structure of active sites to boost OER. Finally, the assembled electrolyzer demonstrates outstanding durability over 1000 h and a voltage of 1.83 V at a current density of 1 A per cm². This spherical geometrical design of electrostatic protection offers insights into catalyst optimization for seawater electrolysis.