N-doped and Cu,N-doped carbon dots as corrosion inhibitor for mild steel corrosion in acid medium

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 653; p. 129905
• Main Authors: Padhan, Subash, Rout, Tapan Kumar, Nair, Udayabhanu G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20.11.2022
• Subjects: adsorption; Carbon dots; corrosion; Corrosion inhibitor; Cu,N-doped carbon dots; EIS; electrochemistry; Mild steel; steel; Cu,N-doped carbon dots; Mild steel; Carbon dots; Corrosion inhibitor; EIS
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2022.129905

In the present study, N-doped carbon dots (N-CDs) and Cu,N-doped carbon dots (Cu,N-CDs) with various Cu doping amounts were explored as corrosion inhibitors for mild steel substrate. Material characterizations of synthesized materials were performed using UV-Vis, FTIR and XRD, TEM and XPS techniques. Electrochemical corrosion testing showed enhanced corrosion inhibition performance for Cu,N-CDs relative to N-CDs. The inhibition efficiencies were directly proportional to concentrations of N-CDs and Cu,N-CDs, with more than 97% achieved at 100 ppm of Cu,N-CDs. Gravimetric measurements at temperatures ranging from 40 to 70 ℃ revealed a slight increase in inhibition efficiencies from 99.5 % to 99.7 % for higher Cu doped Cu,N-CDs. Protective nature of N-CDs and Cu,N-CDs was accredited to physicochemical adsorption and inhibitor film formation. In addition, the growth of an electroless like Cu deposit on the mild steel surface contributed to better inhibition performances of Cu,N-CDs. The inhibition mechanism was supported by surface characterization of inhibited steel substrate. [Display omitted] •High corrosion inhibition efficiency was achieved at low concentrations of Cu,N-CDs.•Cu,N-CDs with higher Cu doping showed no substantial corrosion even at high temperatures.•N-CDs and Cu,N-CDs followed the physicochemical adsorption mechanism.•Electroless like Cu deposition was encountered on mild steel surface in presence of Cu,N-CDs.•Cu,N-CDs could prevent cathodic hydrogen evolution reaction due to Cu deposition.