Ru/Ni3S2@NiO Nanorod Arrays: A Sandwich Armor Electrocatalyst for Efficient and Highly Durable Hydrogen Evolution from Seawater

Abstract Achieving efficient and durable hydrogen evolution from seawater requires catalysts that overcome chloride-induced corrosion while maintaining a high activity. In the current study, we addressed this challenge by designing an advanced sandwich armor catalyst of Ru/Ni3S2@NiO nanorod array. In this architecture, the inner Ni3S2 support disperses Ru and optimizes its electronic structures, the intermediate Ru nanoparticles serve as active sites for hydrogen production, and the outer mesoporous NiO shell enables rapid mass transport to the Ru active sites and enriches surface electrons to repel corrosive Cl–. Results of theoretical calculations and in situ spectroscopy studies validate that this catalyst has an optimized electronic configuration of Ru, favorable water adsorption, and markedly enhanced Cl– resistance. Consequently, the Ru/Ni3S2@NiO nanorod arrays exhibit excellent hydrogen evolution reaction (HER) activity and remarkable durability for over 1000 h of operation in alkaline seawater. Furthermore, when coupled with a commercial silicon solar cell, an electrolytic system composed of Ru/Ni3S2@NiO achieves a high solar-to-hydrogen efficiency of 14.1% in seawater splitting. This work not only provides an effective strategy to address the stability issue of Ru-based materials in harsh environments but also offers ideas and a theoretical basis for the design of high-performance and highly durable electrolytic catalysts for the HER in real complex seawater systems.