Fabrication and characterization of graphene-based carbon hollow spheres for encapsulation of organic corrosion inhibitors

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2018-11, Vol.352, p.909-922
• Main Authors: Haddadi, S.A., Ramazani, S.A.A., Mahdavian, M., Taheri, P., Mol, J.M.C.
• Format: Article
• Language: English
• Subjects: Carbon hollow sphere; Corrosion inhibitor; Graphene-structure; Hard template
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2018.06.063

[Display omitted] •Graphene-based CHSs were synthesized for MBI corrosion inhibitor encapsulation.•The carbon structure of the shells was characterized by Raman spectroscopy and XRD.•pH-dependent release of MBI from the carbon capsules was evaluated using UV–vis.•MBI release from carbon capsules increased with the pH of the NaCl solution.•MBI released from CHSs forms a protective film on mild steel retarding corrosion. In this work, we synthesized carbon hollow spheres (CHSs) using the silica templating method, encapsulated 2-mercaptobenzimidazole (MBI) inhibitor in the CHSs and evaluated their corrosion inhibition performance upon exposure of mild steel to a saline solution containing the released inhibitor. The effects of silica template surface modification on the CHS structure was evaluated, while the structure and morphology of the synthesized CHS was analyzed using field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), Raman spectroscopy and X-ray diffraction (XRD) spectroscopy. Furthermore, thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy mapping (EDS-mapping) and UV–vis were employed to evaluate the MBI release from carbon capsules at different pH values. Corrosion protection performance of the doped CHS was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results showed tunability of the shell structure between an amorphous carbon and graphene structure using surface modification of the silica templates. Moreover, the MBI release from the CHSs showed to be pH-dependent allowing smart protection of mild steel when exposed to corrosive conditions.