Harnessing anion intercalation to activate layered double hydroxides for efficient and stable seawater splitting

Abstract

The direct electrolysis of seawater offers a sustainable pathway for green hydrogen production, yet its practical implementation is constrained by the competing chlorine evolution reaction and severe catalyst corrosion. Layered double hydroxides (LDHs) with their tunable host layers and exchangeable interlayer galleries present a promising catalytic platform for the oxygen evolution reaction (OER) in seawater, though their intrinsic activity and chloride tolerance require further enhancement. Anion intercalation engineering has emerged as a powerful strategy to systematically address these challenges. By inserting functional anions, ranging from simple inorganic ions and polyoxometalates to organic molecules, into LDH interlayers, it is possible to expand interlayer spacing for improved mass transport, directly modulate the electronic structure of metal centers to boost intrinsic OER activity, and create a negatively charged interfacial microenvironment that selectively enriches OH⁻ due to its superior ability to participate in the interfacial reaction network. This review comprehensively examines the design principles, mechanistic insights, and catalytic performance of various anion-intercalated LDHs for seawater splitting. It highlights representative breakthroughs in material design, discusses integration strategies within practical electrolyzer devices, and evaluates long-term stability under industrial operating conditions. Finally, the review outlines key challenges and future research directions aimed at advancing the rational design and scalable deployment of high-performance and durable LDH-based catalysts for sustainable hydrogen production from seawater.