TiO₂ Nanoparticle/Carboxymethyl Cellulose Coatings for Photocatalytic Dye Degradation in Simulated Seawater

In this work, by integrating TiO 2 nanoparticles and sodium carboxymethyl cellulose (CMC) binder, a green bifunctional TiO 2 nanostructured coating (T-SCMC-vac.) directly coupled with 304SS was designed under vacuum thermal treatment, aiming to achieve methyl orange degradation and metal anticorrosion. The T-SCMC-vac. nanostructured coating exhibited a reaction constant 1.7 times higher for degrading methyl orange compared with its counterpart in the simulated seawater environment, demonstrating good photocatalytic performance. Simultaneously, T-SCMC-vac. provided effective photocathodic protection to 304SS. The open circuit potential negatively shifted to −500 mV (vs Ag/AgCl), and the photoresponse current and corrosion current densities reached approximately 10 μA cm –2 . Furthermore, the nanostructured coating showed good stability, as evidenced by 98% retention in photocatalytic capability after five cycles and by 14 h long-term photocathodic protection. The experimental results and theoretical calculations suggest that the enhanced performance can be attributed to the chemical interaction between TiO 2 nanoparticles and CMC via C–O–Ti bonds, which significantly facilitated photogenerated carrier transport and aligned the potential positions of TiO 2, reactive oxygen species, and 304SS. Our findings provide a facile strategy for designing green bifunctional TiO 2 nanostructured coatings on ocean-based facilities with seawater pollutant degradation and metal anticorrosion properties.