Environmentally Friendly Corrosion Protection of Q235 Steel Using Tagetes Patula Flowers-Derived In-Situ Functionalized Carbon Quantum Dots

This study presents an environmentally friendly approach to corrosion protection of Q235 steel using in-situ functionalized carbon quantum dots (CQDs) derived from Tagetes patula (marigold) flowers. Leveraging the natural phytochemicals in Tagetes patula, the CQDs were synthesized through an eco-friendly and green method, which ensured sustainability and minimized the use of hazardous chemicals. The functionalized CQDs were thoroughly characterized using spectroscopic and microscopic techniques to confirm their surface functional groups and structural, morphological, optical, and chemical properties. The corrosion inhibition performance of the CQDs on Q235 steel in 1 M HCl solution was evaluated using electrochemical techniques such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The results demonstrated a remarkable enhancement in corrosion resistance of Q235 steel, attributed to the dense and uniform CQD coating, which acted as an effective physical barrier by coordinating their active functional groups with the iron metal for strong adhesion and passivation that slowed the anodic metal’s dissolution reaction. Furthermore, the alterations in the PDP corrosion potential study showed that the CQDs had a mixed corrosion inhibitory effect. This innovative approach highlights the potential of Tagetes patula-derived CQDs as a cost-effective, sustainable, and efficient solution for mitigating corrosion in industrial applications, paving the way for greener technologies in materials science.