Synergistic lanthanum /nitrogen co-modified carbon dots as steel corrosion inhibitor

Carbon dots have significantly contributed to corrosion resistance due to their varied physical and chemical properties, excellent biocompatibility, and high surface activity. Therefore, designing and developing high-performance carbon dot inhibitors is of great significance. The study successfully synthesized lanthanum and nitrogen co-modified carbon dots (La/N-CDs), which function as a green and effective corrosion inhibitor. It was found that the La/N-CDs inhibitor presented a nanostructure with size of 3–9 nm. Electrochemical experiments, such as Tafel plots and EIS, showed that the presence of La/N-CDs effectively suppressed metal corrosion in a chloride-containing corrosion solution. In a 3 wt% NaCl solution, 400 mg/L La 15 % /N-CDs exhibited the best corrosion inhibition performance, with an impedance modulus of 2165.33 Ω cm² and an inhibition efficiency reaching as high as 93.07 %, while the surface roughness of the steel and the corrosion rate was also minimized. This might be explained by the formation of an adsorption layer by La/N-CDs on the metal surface, a phenomenon confirmed by Langmuir isotherm and XPS investigations. These findings confirmed that La/N-CDs could form a protective film on the metal surface, significantly improving its corrosion resistance and extending its service life in corrosion environment. The study’s findings offered insights and a conceptual structure for enhancing corrosion inhibitors using carbon dots that were augmented with rare earth elements.