Biofouling protection for marine optical windows by electrolysis of seawater to generate chlorine using a novel Co-based catalyst electrode

Ocean optical windows suffer serious biofouling, and electrochemical chlorination has been proposed as an innovative protective way. In this work, Co-based catalysts consisting of Co and Co(OH)2 were electrodeposited on Ti foils via the facile chronoamperometry technique, and their catalytic activity towards chlorine evolution reaction (CER) was investigated. The results showed the morphology and activity of catalysts varied with electrodeposition potential and time, and Ti foils electrodeposited at −1.5 V (vs. SCE) for 400 s held the highest CER catalytic activity. Co and Co(OH)2 transferred into Co3O4 at potentials more negative than CER, and it was Co3O4 that behaved as the catalyst. The CER selectivity of Co-based catalysts (–1.5 V, 400 s) was higher than 80% at current densities of 1–20 mA/cm2, and they also gave good stability. The bactericidal ratio of active chlorine concentration produced by chronoamperometry on Ti foils modified with catalysts towards Pseudomonas aeruginosa and Staphylococcus aureus was nearly 100% after 50 min of electrolysis. Furthermore, good antifouling of optical lens in seawater was achieved by a designed electrochemical chlorination accessory equipped with the as-prepared catalyst electrode. This work sheds light on the application of Co-based catalysts in antifouling of optical windows by electrochemical chlorination.