2D g-C3N4/sodium alginate-chitosan photocatalytic hydrogel coating with electron-rich microenvironment remarkably enhances synergistic antibacterial and anticorrosive action

Abstract

Hydrogel coatings demonstrate potential for protecting against microbiologically influenced corrosion; however, they encounter limitations related to weak mechanical properties and toxicity from chemical crosslinkers. In this study, we prepared a photocatalytic antibacterial hydrogel coating using chitosan and sodium alginate loaded with 2D g-C₃N₄, which exhibited robust tensile properties, low swelling rates, and exceptional antibacterial efficacy against Escherichia coli and Staphylococcus aureus. The antibacterial activity is primarily attributed to the adsorption of bacteria by –NH₂ groups and the generation of reactive oxygen species by 2D g-C₃N₄. Furthermore, the electron-rich microenvironment created by –NH₂ and –OH groups attract the h⁺ generated during 2D g-C₃N₄ photocatalysis, thereby enhancing the efficiency of charge carrier separation. Density functional theory calculations further support this conclusion. The incorporation of 2D g-C₃N₄ nanomaterials alters the hydrogel coating structure, disrupting hydrogen bonding and exposing additional –NH₂ groups that bind with H⁺ to improve active adsorption. This innovative hydrogel coating offers a novel strategy for protecting against microbial corrosion in marine environments.