Palladium-chloride ion coordination stabilizes NiFe layered double hydroxides for alkaline seawater oxidation at industrial current densities

Abstract

Seawater electrolysis represents a promising route for sustainable hydrogen production, offering substantial potential for large-scale energy conversion applications. However, ample chloride ions (Cl⁻) in seawater promote competitive chlorine evolution reaction at the anode, compromising oxidation selectivity and significantly shortening electrode lifespan, particularly under industrial-level current densities (j). In this study, a self-supported Ni-foam electrode was synthesized by anchoring palladium (Pd) nanoparticles on NiFe layered double hydroxide (Pd@NiFe LDH/NF) to serve as a robust catalyst for alkaline seawater oxidation (ASO). Pd nanoparticles not only improve electrical conductivity and enhance ASO activity but also spontaneously coordinate with Cl⁻, effectively mitigating active site degradation through the common-ion effect. Notably, Pd@NiFe LDH/NF delivers a j of 1 A cm⁻² at an overpotential of 370 mV and operates stably for over 500 h, highlighting its high activity and long-term durability. This study offers critical guidance for the rational design of Cl⁻-resistant anode catalysts, presenting a viable strategy to overcome corrosion challenges during the ASO process