Designing a dual-functional material with barrier anti-corrosion and photocatalytic antifouling properties using g-C3N4 nanosheet with ZnO nanoring

As a semiconductor material with a 2D-laminate structure, g-C 3 N 4 (bandwidth 2.7 eV) has a similar structure and excellent performance to graphene. However, high surface energy and photogenerated e–h recombination of g-C 3 N 4 seriously hinder its application in the field of marine anticorrosion and antifouling. To solve these problems, we synthesized the g-C 3 N 4 nanosheets decorated with ZnO nanoring via chemical etching technology. Whether the NR ZnO-CNNs have surface protection performance among the pure EP on the corrosion protection for metal substrate were investigated. The antifouling properties NR ZnO-CNNs hybrid were also estimated through photocatalytic bacterial and algae resistance tests. Combined with the electrochemical results, it was found that the impedance modulus of NR ZnO-CNNs/EP within 45 days showed two orders of magnitude higher than that of pure EP in the 3.5 wt% NaCl solution. Besides, Local electrochemical impedance spectroscopy (LEIS) further explored the anticorrosion behavior of NR ZnO-CNNs/EP coating, which indicated that the NR ZnO-CNNs/EP coating with a scratch maintained an excellent corrosion resistance between 0–24 h. Under the visible light conditions, the lifetime of photogenerated e–h was prolonged due to the formation of NR ZnO-CNNs heterojunction structure, it was observed that the antibacterial rate against Bacillus subtilis reached 100% within 8 h. An Antialgae test was performed on chlorella seawater solution, which indicated that 5 mg/mL of NR ZnO-CNNs hybrid could make chlorella sharply reduce within 4 days. Simultaneously, the corrosion protection and photocatalytic antifouling mechanisms of NR ZnO-CNNs were proposed, thus it provided a broader platform for the design of versatile marine protection materials.