Dopamine functionalized graphene oxide (DGO) as a corrosion inhibitor against X60 carbon steel corrosion in a simulated acidizing environment; An electrochemical, weight loss, SERS, and computational study

This study examines the effectiveness of dopamine-functionalized graphene oxide (DGO) as a corrosion inhibitor for carbon steel in a 15 % HCl solution simulating an oilfield acidizing corrosive environment. Experimental electrochemical and weight loss techniques were used for the evaluation, complemented by surface analytical methods such as FTIR, SEM/EDS, and AFM. The influence of temperature on the performance of the inhibitor was also studied. The adsorption behavior of DGO at different concentrations was studied using surface-enhanced Raman scattering (SERS). Computational tools were also used to understand the mode of adsorption of the inhibitor molecules on the steel surface and the nature of the interaction between the silver nanoparticles used in the SERS study and the inhibitor molecules. DGO showed a maximum inhibition efficiency of over 85 % at room temperature at the optimum concentration of 5 ppm as observed in the weight loss and electrochemical studies. The inhibitor behaved like a mixed-type according to the PDP measurement and obeyed the Langmuir adsorption theory. SEM/EDS, AFM, and FTIR analyses of the steel surface after 24 h of immersion in the test solution confirmed the adsorption of the inhibitor on the steel surface to form a protective layer that protects the steel from aggressive attack by corrosive media. The intensity of SERS showed a strong correlation with the electrochemical and weight loss results. Computational analysis revealed that the primary adsorption mechanism of DGO molecules on the carbon steel surface involves the bonding between the steel surface and the aromatic rings of the GO component. This research is significant as it addresses two major environmental issues: corrosion and waste disposal using GO derived from waste graphite powder. The SERS technique used in this study has the potential to serve as a sensor to monitor the dynamic adsorption of corrosion inhibitors irrespective of the type of metal.