Mechanistic Insights into the Corrosion Inhibition Performance of Eco-Friendly Nitrogen and Boron Co-Doped Carbon Dots for Mild Steel in a 15% HCl Solution

A novel and eco-friendly route to synthesize boron, nitrogen codoped carbon dots using aniline, citric acid, and boric acid as precursor materials has been used successfully to reduce mild steel corrosion. This report describes the detailed weight-loss experiments, electrochemical measurements, and surface morphology analysis conducted to explore the efficacy of B,N-CDs as a highly effective corrosion controller for mild steel (MS) protection in 15% hydrochloric acid (HCl). The findings specify that B,N-CDs significantly decreased the corrosion of MS and attained an inhibition capacity of up to 96.7% at 75 ppm. The protection of the MS surface occurs through the generation of a protective film through adsorption of the B,N-CDs. The corrosion inhibitor undergoes predominant physisorption, which is confirmed by the values of ΔGads. Electrochemical studies further established that B,N-CDs act as a mixed type corrosion inhibitor. Hence, the aforementioned carbon dots are both cathodic and anodic corrosion inhibitors for MS. The XPS of the inhibitors explained that it is of inorganic/organic hybrid nature of the protective film generated on the surface of the substrate. The findings represent a new highly effective corrosion inhibitor that outperforms most of the alternatives at lower concentrations.