Quantum dots as ecofriendly and aqueous phase substitutes of carbon family for traditional corrosion inhibitors: A perspective

Carbon dots (CDs) or quantum dots (QDs) are a new and rising member of the carbon family that has withdrawn substantial academic and industrial attention. Unlike to most of the carbon allotropes such as CNTs, graphene and fullerene, CDs are associated with numerous advantages including substantial biocompatibility, high quantum yield, magnified adsorption ability, excellent electric conductivity, low toxicity, cost-effectivity, eco-friendliness, high solubility and excellent stability. Because of their ecofriendly and high solubility, recently CDs are being used as aqueous phase corrosion inhibitors. Literature inspection suggests that CDs derived from citric acid, ammonium citrate, urea, L-histidine and thiourea exhibit remarkable anticorrosive activity. Spectroscopic techniques such as SEM, TEM, HRTEM, AFM, FT-IR, UV–vis, EDX and XPS are mainly employed to characterize the developed CDs. Literature outcomes suggest that N doped, N,S co-doped and chemically modified CDs exhibit higher anticorrosive activity than purified CDs. The CDs mostly behave as mixed- and interface-type inhibitors. Adsorption of CDs on metal surfaces mostly followed the Langmuir adsorption isotherm. Surface investigations principally SEM, AFM, EDX and XPS analyses are widely conducted to demonstrate the corrosion inhibition using CDs.