<scp>l</scp>-Tyrosine-Derived Nitrogen-Doped Carbon Dots Synthesized via a Hydrothermal Approach for Corrosion Mitigation of Mild Steel in 15% Hydrochloric Acid Solution

l-Tyrosine-based eco-friendly nitrogen-doped carbon dots have been synthesized using citric acid and isoniazid as precursors along with l-tyrosine via a facile one-pot hydrothermal approach for the corrosion mitigation of mild steel (MS) in HCl solution (15%). The authenticity of the synthesized carbon dots has been established using various spectroscopic techniques such as X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), and Fourier transform infrared (FT-IR) spectroscopy. The inhibition behavior was studied using gravimetric analysis, electrochemical measurements, and surface analysis. The potentiodynamic polarization revealed that the N-doped carbon dots act as a mixed-type corrosion inhibitor; that is, it can act as both a cathodic as well as an anodic inhibitor, with the corrosion efficiency of 99.3% at the concentration of 150 ppm. N-CDs protect the metal surface by forming a layer that is particularly physisorbed as confirmed by Δ<i>G</i>_abs values.