The recent development of carbon dots as powerful green corrosion inhibitors: A prospective review

The corrosion of metallic materials in aggressively acidic, saline, CO2-saturated saline and microbiological solutions is a continuous problem in the oil and gas industry. Using carbon dots (CDs) in corrosion protection is an ecological and environmentally efficient method because CDs have good water solubility, biocompatibility, low toxicity, excellent antibacterial properties, chemical stability, high thermal activity, and nonflammability. The inhibition performance of CDs was over 95–99% at low concentrations and medium temperatures. The CDs contain more pyrrole-like N, pyridine-N, graphitic N atoms and O atoms, in which the lone electron pairs promote CDs to become efficient corrosion inhibitors. The CDs formed rigid covalent bonds with the metal surface through π-electrons transfer. The CDs easily substituted with the pre-adsorbed water on the metal surface. In this review, the inhibition, adsorption, electrochemistry, surface morphology and structural characteristics of CDs for steel, copper and aluminium in aggressively acidic, saline, CO2-saturated saline and microbiological solutions are reviewed and discussed.