Na-CDs as an eco-friendly and efficient corrosion inhibitor for Q235 in 1 M HCl

In this study, a novel type of green and highly efficient Na-CDs corrosion inhibitor was successfully prepared using a hydrothermal method, and its properties were thoroughly characterized. The results revealed that the NaCDs possessed a uniform nanoscale size distribution and a well-defined graphene lattice structure. The corrosion inhibition performance of Na-CDs at varying concentrations was assessed, and it was found that the corrosion inhibition efficiency initially increased with the increase of concentration, peaking at over 96 % when the concentration reached 150 mg/L, before subsequently declining. Analysis of the adsorption behavior of Na-CDs on the metal surface confirmed that the adsorption process followed the R-P adsorption isotherm, indicative of an almost ideal homogeneous monolayer adsorption. The corrosion inhibition mechanism is the result of forming a protective film on the metal surface by physical adsorption and chemical adsorption, with the bridging role of Clfurther reinforcing the structure of this film. However, at excessively high concentrations of Na-CDs, desorption occurred, compromising the integrity of the protective film. This study enriches the field of metal-doped carbon dots as corrosion inhibitors and provides insights into the synthesis of carbon dots and the development of carbon dot-based corrosion inhibitors.