Poly(Acid Yellow 17)-Modified CoFe-Layered Double Hydroxide Achieves Long-Term Alkaline Seawater Oxidation

Seawater electrolysis powered by renewable energy is a promising technique for green hydrogen production. However, the high concentration of chloride ions (Cl–) and their derivatives in seawater can severely corrode the anode catalyst, significantly challenging the lifespan of electrolyzers. Herein, we present a poly(acid yellow 17) (PAY) layer-modified CoFe-layered double hydroxide nanoarrays on nickel foam (CoFe LDH@PAY/NF), which serves as an efficient and stable electrocatalyst for alkaline seawater oxidation (ASO). PAY layer functions as an electrically conductive layer, which significantly enhances the conductivity of CoFe LDH/NF and thus improves the catalytic activity of ASO. Moreover, the sulfonic acid groups of PAY create a negatively charged environment on the surface of CoFe LDH/NF, effectively repelling Cl–, while the chlorine atoms in PAY form a Cl–-free protective layer on the surface. These two mechanisms work synergistically to stabilize the seawater electrolysis process. Electrochemical test data indicate that CoFe LDH@PAY/NF achieves a current density of 1000 mA cm–2 at just 336 mV for ASO. The CoFe LDH@PAY/NF demonstrated superb stability, exhibiting slight activity degradation after 800 h ASO under 1000 mA cm–2. This work provides important guidance for developing anode catalysts resistant to Cl– corrosion during the ASO process.