Ionic liquid-assisted preparation of N, S-rich carbon dots as efficient corrosion inhibitors
By Wang, Tianxiang; Cao, Shuyun; Sun, Youqing; Liu, Dan; Pan, Shiguang; Ma, Aijing; Kuvarega, Alex T.; Mamba, Bhekie B.; Gui, Jianzhou
Published in Journal of Molecular Liquids
2022
Abstract
A series of (N, S-rich) carbon dots were prepared from L-cysteine via the typical solvothermal method with 1-butyl-3-methylimidazolium bromide as the solvent by varying synthesis time. The experimental results indicated that the carbon dots synthesized for 60 min, the biggest in average carbon dot sizes (about 117.0 nm), highest pyrrole-like N contents (62.9%), showed the best corrosion inhibition performance with a high efficiency of 97% at 40 mg/L of inhibitors for carbon steel in 0.5 M H2SO4 solution, which was ascribed to the fact that the adsorption of the carbon dots followed the Langmuir adsorption model. Correspondingly, a potential corrosion inhibition mechanism was proposed by surface characterization results, and the parallel adsorption mode of pyrrole-like N species on steel surface by π-complex formation contributed dominantly to the excellent inhibition performance. The work provided a general solvothermal method for carbon dots inhibitor synthesis assisted by ionic liquids, and the structure-inhibition relationship gave the guideline for the theoretical design of corrosion inhibitors.