Design and Synthesis of Mosaic ZnO/g-C₃N₄ Heterojunction Materials with Excellent Anticorrosion Performance

Photocathodic protection was considered an economic and environmentally friendly metal protection method. To overcome the low electron transfer efficiency and poor reduction capability, the heterojunction was constructed based on traditional inhibitors for expanding the application prospect and increasing photocathodic efficiency. A Z-type ZnO/g-C3N4 heterojunction (ZCN) material with a mosaic structure was obtained under hydrothermal conditions. The ZCN material induced photocarriers to accumulate on the iron substrate surface through the internal electric field and increased the electron capacity through protonation reactions of pyridinic nitrogen atoms. Meanwhile, the labyrinth effect of the two-dimensional structure prolonged the penetration path of the corrosive substances. These protection effects functioned synergistically to reduce the corrosion rate to a significant extent, in which the impedance value of the ZCN coating increased by 1128.9% compared with epoxy coating. This study provides an approach to improve the corrosion inhibition efficiency of traditional inhibitors by constructing anticorrosive heterojunction materials.