Abstract: Carbon dot inhibitors (UTCDs, HSCDs) are successfully prepared for the first time by ultrasonic treatment and hydrothermal synthesis from Camellia oleifera shells (COS), respectively. The fluorescence properties and structures of UTCDs and HSCDs, as well as their corrosion inhibition and adsorption mechanisms on cold rolled steel (CRS) in trichloroacetic acid (Cl₃CCOOH) solution, are investigated in depth. It is found that HSCDs exhibit stronger fluorescence and higher corrosion inhibition performance than UTCDs at a lower dose (300 mg L^-1, 91.6 %). They possess amorphous carbon matrix, crystalline regions, surface functional groups, and active compounds. HSCDs have multiple protective mechanisms, including forming physical barriers, reducing oxides, and depleting C and O atoms in the corrosive medium. The enhancement of synthesis methods enables the mass production of HSCDs that effectively prevent corrosion.

Key words: Carbon dots, Corrosion inhibition, Camellia oleifera shells, Trichloroacetic acid