An Integrated Stainless Steel-Based Electrode for Durable Direct Natural Seawater Electrolysis.

Abstract

Direct seawater electrolysis for hydrogen production is hindered by severe catalyst inactivation and material corrosion caused by the complex composition of natural seawater. In this work, we demonstrate a multistage structure on a stainless steel (SS) substrate by integrating Pt atomic clusters (0.044 wt%) with a dense NiFe layer double hydroxides (NiFe-LDH) anticorrosive coating. The assembled seawater electrolyzer maintains durable operation for 600 h at a current density of 400 mA cm^-2 (∼2.04 V) and for 1000 h at 200 mA cm^-2 (∼1.78 V), while simultaneously achieving a cost reduction of more than 40% and ultralow energy consumption of 4.26 kWh Nm^-3 H₂. Multiple in situ characterization results reveal that the adsorbed H₂O molecules between the interface of Pt atomic clusters and NiFe-LDH could initiate a potential-driven dynamic transformation process from a 4 hydrogen-bond to a 0 hydrogen-bond coordination of H₂O, thereby promoting their dissociation. Pt atomic cluster induces a configuration transformation of interfacial water from two-H down to two-H up and differentiates the adsorption energies between H₂O and chloride ions, further optimizing selectivity. This work fully demonstrates the integrated design of catalysts, anti-corrosion coating, and porous transport layer, thereby offering an innovative and practical approach to direct seawater electrolysis.