Facile and scalable preparation of carbon dots with Schiff base structures toward an efficient corrosion inhibitor

Carbon dots (CDs) have been demonstrated to be a novel, green and effective corrosion inhibitor. Nevertheless, it still remains an enormous challenge to obtain CDs corrosion inhibitors by an energy-efficient and time-saving way. Meanwhile, there is no investigation to evaluate the inhibition effect of CDs with Schiff base structures. To surmount the barrier, a facile and scalable approach is elaborately designed to prepare CDs with Schiff base structures (Sc-CDs) by Schiff base reaction using o-phenylenediamine (o-PD) and p-benzoquinone (p-BQ) as precursors at 50 °C for 2 h, and their corrosion inhibiting properties for Q235 carbon steel in 1 M HCl solution are systematacially investigated by weight loss test, electrochemical impedance spectra (EIS) and potentiodynamic polarization (PDP) measurement for the first time. Significantly, Sc-CDs with a long-term dispersion stability in HCl solution reveal a prominent inhibition efficiency of >96 % only at 200 mg/L incorporation. And according to the analyses of electrochemistry, adsorption isotherm and corrosion morphology, the inhibition mechanism of Sc-CDs is rationally attributed to the protective film established by Sc-CDs chemical and physical adsorptions. This work not only provides a facile, scalable, energy-efficient and time-saving approach to synthesize CDs, but also firstly evidences significant inhibition capacities of CDs with Schiff base structures. These findings would dramatically stimulate the development of truly low-cost and high-efficiency CDs corrosion inhibitors.