BackgroundCarbon dots (CDs) can be designed as an effective assembly unit to construct the intelligent corrosion inhibition system. Compared to purified CDs, the doped CDs have more advantageous anti-corrosion performance. However, the reported nitrogen-doped CDs usually have a low N/C atomic ratio. The increase of the N/C ratio has an important significance in improving the properties of nitrogen-doped CDs for corrosion protection. MethodsThe high-nitrogen-doped CDs (N-doped CDs) are prepared from melamine and fructose via solvothermal treatment. The corrosion inhibition effect of the N-doped CDs for copper in 3wt% NaCl solution is studied by electrochemical measurements, surface characterizations and fluorescence spectrum analyzer. It demonstrates that the N-doped CDs can protect the copper in 3wt% NaCl solution effectively. Significant findingsThe nitrogen content of the N-doped CDs is improved to 23.95%.The optimal inhibition efficiencies reach 96.1% at 200 mg⋅L−1 of the N-doped CDs. The N-doped CDs can form a compact protective film on copper surface via adsorption and chelation with cupric ions.