N-doped carbon dots as a multifunctional platform for real-time corrosion monitoring and inhibition

The occurrence of corrosion can't be completely eliminated. To prevent the failure of structural materials, corrosion has to be easily identified, visualized and detected at early-stage, in order to intervene at the point where it is necessary. In this view, fluorescent N-doped CDs have been synthesized to synergistically inhibit and monitor corrosion of iron. The as-prepared CDs were fabricated by simple solvothermal process using citric acid as carbon source and ammonia as dopant. It is found that the active groups on the surface of the CDs promote the formation of adsorption film of CDs on iron plates and effective fluorescence emission. As a result, the CDs could readily inhibit the corrosion of iron and exhibit an inhibition efficiency of 88 % at 180 mg/L. As the degree of corrosion increases, the CDs-adsorption film can sensitively, visually and effectively respond to released Fe3+ due to the complexation between CDs and Fe3+. Due to this dual function of CDs for corrosion monitoring and inhibition, they can readily trace early-stage corrosion and prevent its development. This is a synergistic strategy to prevent critical engineering failures and to ensure the safety of structural metal materials.