Light-induced in situ reconstruction of CoOOH-modified TiO2/CoNi-LDH heterojunction photoanode: achieving excellent photoelectrochemical cathodic protection and bacterial inactivation

Abstract Corrosion and biofouling of metals in marine environments are critical issues affecting the long-term stability of marine engineering infrastructure. Traditional protection methods suffer from limitations such as high energy consumption and environmental pollution. Photoelectrochemical cathodic protection (PECCP) technology utilizes solar energy to drive the transfer of photogenerated electrons from semiconductors to metal surfaces, enabling green and low-energy-consumption corrosion protection. However, its core challenge lies in developing efficient and stable photoelectrode materials. In this study, a TiO 2 /CoNi-LDH composite photoanode was fabricated via hydrothermal and electrodeposition methods. It was found that under illumination, CoNi-LDH undergoes in situ reconstruction to generate CoOOH as a cocatalyst. The composite material exhibited excellent photoelectrochemical cathodic protection performance in a simulated seawater environment, providing a potential shift of 380 mV for coupled 304 stainless steel under intermittent illumination. Simultaneously, it demonstrated high antibacterial efficiency, achieving a 100% inactivation rate against Pseudomonas aeruginosa within 120 min. Structural characterization and theoretical calculations revealed that the in situ formation of CoOOH enhances interfacial charge transfer and promotes the generation of reactive oxygen species, thereby synergistically improving the anti-corrosion and anti-biofouling performance of the material. This study provides a novel strategy for developing integrated marine protective materials with long-term corrosion resistance and biofouling prevention capabilities.