Poly(phenol red) modified CoFe-layered double hydroxide achieves stable seawater oxidation at an ampere-level current density

Abstract

Seawater electrolysis is considered a sustainable, efficient, and highly promising technology for hydrogen production. However, the high concentration of Cl− in seawater is easily oxidized to produce harmful chloride, seriously affecting the selectivity and stability of the anodic materials. Here, we report a conductive polymer, poly (phenol red) (P(PhR)), to modify CoFe layered double hydroxide arrays on Ni foam (CoFe-LDH@P(PhR)/NF). P(PhR) not only improves the alkaline seawater oxidation performance of CoFe-LDH/NF, but also effectively repels Cl−, thereby improving the stability of CoFe-LDH/NF during alkaline seawater oxidation process. CoFe-LDH@P(PhR)/NF only requires an overpotential of 354 mV to achieve a current density (j) of 1000 mA cm−2 and demonstrates stability for 600 h in alkaline seawater. Only trace amounts of active chlorine are produced during seawater electrolysis process. The electrolytic device assembled with CoFe-LDH@P(PhR)/NF and Pt/C/NF in alkaline seawater can achieve a j of 300 mA cm−2 at a low voltage of 2.17 V and can achieve stability for up to 150 h.