Engineered active Co sites in ternary NiFeCo-layered double hydroxide nanoarrays for highly-efficient photocathodic protection of 304 stainless steel in the dark

To achieve prolonged photocathodic protection (PCP) of 304 stainless steel (304SS) in marine environments, effective charge mobility and electron storage within the photoanodes are essential. In this study, ternary NiFeCo-layered double hydroxide nanoarrays on titanium foil (Ti/NiFeCo-LDH) were synthesized to enable PCP for 304SS. The engineered active Co sites in Ti/NiFeCo-LDH play a dual role: they adjust the electronic and band structures and act as efficient reductants, creating oxygen vacancies that enhance electron transfer from Ti/NiFeCo-LDH to 304SS. Consequently, the fabricated Ti/NiFeCo-LDH exhibits highly efficient PCP for 304SS in simulated seawater, achieving an open circuit potential (OCP) of −803 mV in the dark and maintaining a consistent potential of -760 mV over 82 h. This research presents a significant advancement in developing efficient photoanodes for PCP in metallic materials.