Amphiphilic carbon dots as high-efficiency corrosion inhibitor for N80 steel in HCl solution: Performance and mechanism investigation

Three amphiphilic carbon dots (CDs, C6-CDs, C8-CDs, and C12-CDs) were synthesized and first adopted as a corrosion inhibitor for mild steel. The inhibition behavior of amphiphilic CDs for N80 steel in hydrochloric acid solution was studied via weight loss tests, surface characterization, and electrochemical measurements. Results confirmed that they could protect N80 steel effectively; the longer the carbon chain was, the better the inhibition effect was. Specifically, the inhibition efficiency of C12-CDs reached 92.9 % at 150 mg/L. Moreover, due to the fluorescence characteristics of CDs, the changes in adsorption film during corrosion could be directly observed under UV light. A dense adsorption film was formed through the electrostatic interaction with CDs and the metal surface. Long carbon chains formed a hydrophobic layer on the surface of N80 to isolate the corrosive medium.