Hydrothermal synthesis of peanut shell-derived carbon dots as the novel efficient inhibitor for the corrosion of steel

In this study, a facile and environmentally friendly method was reported for the preparation of carbon dots derived from peanut shells (PS-CDs), a common agricultural waste materials. The synthesized PS-CDs exhibited remarkable effectiveness in inhibiting the corrosion of cold-rolled steel (CRS) in 1.0 M HCl solution. The structural features of PS-CDs were fully confirmed by a combination of characterization techniques, including transmission electron microscopy (TEM), X-ray diffraction (XRD), photoluminescence spectroscopy (PL), ultraviolet-visible absorption spectroscopy (UV–vis) and Fourier-transform infrared spectroscopy (FT-IR). Weight loss measurements revealed that, at 30 °C, the addition of 50 mg L⁻¹ PS-CDs resulted in an inhibition efficiency as high as 92.37 %. The adsorption behavior of PS-CDs on the CRS surface was found to follow the Langmuir monolayer adsorption isotherm. Electrochemical measurements further demonstrated that PS-CDs acted as a mixed-type inhibitor, effectively suppressing both the cathodic hydrogen evolution reaction and the anodic metal dissolution process. Surface analyses indicated that PS-CDs could strongly adsorb onto the CRS surface to form a protective film, thereby significantly mitigating the acid-induced corrosion. The excellent inhibition performance of PS-CDs, combined with their eco-friendly and simple synthesis route, highlights their great potential as a novel green corrosion inhibitor for industrial applications. This also offers a novel promising pathway for the high-value utilization of peanut shell resources.