Facile synthesis of N-doped carbon dots (N-CDs) for effective corrosion inhibition of mild steel in 1 M HCl solution

Abstract

N-CDs, as a novel and eco-friendly inhibitor, were synthesized easily by hydrothermal carbonization technique aiming to inhibit mild steel corrosion in 1 mol. L− 1 HCl. XRD, TEM, SEM, FTIR, UV-vis spectrophotometer and photoluminescence (PL) were utilized to characterize N-CDs. Potentiodynamic polarization and electrochemical impedance spectroscopy techniques along with the complementary surface studies were combined to investigate the corrosion inhibition capability of N-CDs for MS. N-CDs were found nanometer-sized (≈ 4 nm) with quasi-spherical morphology and high crystallinity. Inhibition efficiency, directly proportional to concentration but inversely with temperature, was measured as high as 96.73% (PDP) and 95.21% (EIS) at 200 mg. L− 1. Inhibition mechanism refered mainly to adsorption process that good obeyed Langmuir adsorption isotherm. The surface studies, quantitatively verified by EDX, showed a smoother surface of MS in presence of the N-CDs. Furthermore, the UV- visible spectroscopy effectively revealed the complexations between iron and metal surfaces.