Researchers synthesized nitrogen & sulfur co-doped carbon dots from dried lycium biomass using hydrothermal processing at 200°C for 6 hours. These carbon dots achieved 88.4% corrosion inhibition efficiency for carbon steel in 1 M hydrochloric acid solution at 100 mg/L concentration. The carbon dots averaged 20.3 nanometers in diameter & contained 65.3% pyrrolic nitrogen that enables π-complex formation through parallel adsorption on steel surfaces. Surface analysis confirmed protective film formation through combined physical & chemical adsorption mechanisms. The biomass-derived approach demonstrates sustainable green chemistry principles for industrial corrosion protection.