Synthesis and multifunctional application of two novel carbon quantum dots as corrosion inhibitors

N, S- and N-doped carbon quantum dots (CDs) were synthesized by calcination in the presence of L-cysteine and 2-aminobutyric acid by using P-phenylenediamine as the raw material. The CDs were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and fluorescence spectroscopy. Results show that both kinds of CDs have spherical structures and particle sizes. The CDs were dispersed in 3.5 wt% NaCl solution and doped into the epoxy coating to prepare the composite coating. The two kinds of CDs have good corrosion inhibition effects in both applications.