Dual-target stabilization and antifouling via S-scheme Cu2O@TiO2 heterojunction for robust marine coating under illumination

Improving the performance of antifouling coating under illumination-involved harsh environments is of prime scientific and engineering importance. However, it still remains a big challenge due to the strong photo-corrosion character of cuprous oxide (Cu 2 O) that works as the most widely-used primary antifoulant. To address this issue, a novel heterojunction of Cu 2 O@TiO 2 was constructed by in situ adsorption-hydrolysis approach. The as-designed heterojunction structure endows superior photo-stability with Cu 2 O@TiO 2 , which has been proven to proceed via S-scheme mechanism by a set of complementary characterizations including in situ XPS and EPR. As anticipated, the resulted Cu 2 O@TiO 2 coating manifests excellent stability and antifouling performance under illumination-involved mimetic service conditions such as dry-dock and waterline environments, as substantiated by the bioassays and marine field trials. A dual-target photo-synergized enhancing mechanism for the S-scheme Cu 2 O@TiO 2 could be deduced as to: (i) inhibit the accumulation of holes on Cu 2 O to exert a stabilization effect; (ii) boost the generation of reactive oxygen species (ROS, including HO /O 2 − ) to enhance the antifouling property. The methodology provides a proof-of-concept design to fabricate high photo-stable Cu 2 O-based antifoulant materials, with the gain in understanding the intrinsic failure principle of coatings and the biocidal mechanism of cuprous oxide toward marine application.