Chemical Oxidation Synthesized High‐yield Carbon Dots for Acid Corrosion Inhibition of Q235 Steel

Abstract In this work, high‐yield carbon quantum dots (CQDs) are successfully synthesized by a simple chemical oxidation method using acetaldehyde as raw material. Fourier‐transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), thermogravimetry (TGA), and XPS are used to analyze the structural characteristics of CQDs. The results demonstrate that many oxygen‐containing functional groups are on the surface of carbon nuclei. The inhibitive efficiency of electrochemical experiments and weight loss is 87.1 % and 95.3 %, respectively. SEM observes the surface morphology of the sample after 72 h corrosion with or without CQDs, and EDS analysis confirms that CQDs are effectively adsorbed on the surface of carbon steel. Furthermore, through calculation, the standard adsorption‐free energy of CQDs is −25 kJ/mol, concluding that the adsorption process is a combination of physisorption and chemisorption. This work is helping to solve the corrosion problem of metal equipment in the acid process.