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.