Carbon dot aggregates: A new strategy to promote corrosion inhibition performance of carbon dots

The corrosion of metal not only produces serious economic losses and environmental pollution but also threatens equipment safety. Carbon dots (CDs) exhibit outstanding inhibition properties to availably retard the corrosion of metal. However, the present CDs-based corrosion inhibitors still fail to fully exert the environmentally friendly and low-cost merits of CDs. To address this issue, CD aggregates (CDAs) prepared by low-cost and eco-friendly CDs are developed as novel corrosion inhibitors for the first time, and their corrosion inhibition mechanism is disclosed. Specifically, CDAs with excellent long-term dispersion stability are synthesized by solvothermal treatment of CDs formed by citric acid and urea. CDAs at only 200 mg/L provide a corrosion inhibition effect of 90.38% for Q235 carbon steel in 1 mol/L HCl solution, approximately 1.53 times higher than that of CDs (59.21%). Moreover, the corrosion inhibition mechanism of CDAs is proposed through the analysis of adsorption isotherm, examination of corrosion morphologies, and theoretical calculations. That is, CDAs physically and chemically adsorb on the carbon steel surface, mainly hindering its anodic reaction, thus retarding the corrosion of carbon steel. This research firstly verifies the corrosion inhibition potential of green and low-cost CDAs and provides a novel strategy to promote the corrosion inhibition performance of CDs, promoting the progress of aggregate-based corrosion inhibitors.