Synthesis, characterization and anti-corrosion property of graphitic carbon nitride for carbon steel in acid medium

Abstract

The present study involved the synthesis of a 2D material known as graphitic carbon nitride (g-C3N4) using solvothermal method and characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Gravimetric and electrochemical methods, including electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), electrochemical frequency modulation (EFM), and potentiodynamic polarization (PDP), in combination with surface analysis techniques such as SEM, EDS, optical profilometry (OP), and atomic force microscopy (AFM) are used to confirm its anti-corrosive properties. The findings revealed that the effectiveness of g-C3N4 increased proportionally with higher concentrations, reaching its peak potency of 85.0 % at a concentration of 100 ppm. Remarkably, the effectiveness of inhibition increased as the temperature rose until it reached 40 °C, but then decreased as the temperature continued to increase up to 60 °C. Density function theory and molecular dynamic simulation were used to correlate the experimental data to explain the intrinsic properties of g-C3N4 and the adsorption mechanism. The primary mechanism of corrosion inhibition was found to be the adsorption of g-C3N4 onto the steel surface. This was confirmed through surface analysis using SEM, EDS, AFM, OP and computational study.