NiFe layered double hydroxide with intercalated fluorosilicate anions for industrial-level alkaline seawater oxidation

Abstract

Seawater electrolysis for hydrogen production is efficient and promising, but chloride ions (Cl⁻) cause severe anode corrosion, limiting its potential. In this study, we present the intercalation of fluorosilicate anions into NiFe layered double hydroxide nanosheet arrays on Ni foam (SiF₆²⁻-NiFe LDH/NF) as an industrial-level alkaline seawater oxidation catalyst. SiF₆²⁻-NiFe LDH/NF achieves a current density of 1000 mA cm⁻² at an overpotential of 371 mV and maintains good stability for 1000 h. It also exhibits robust stability at higher current densities of 1.5 and 2 A cm⁻². In situ Raman spectroscopy confirms that SiF₆²⁻ promotes the generation of γ-NiOOH and repels Cl⁻, demonstrating excellent tolerance under extreme conditions.