Preparation, characterization, and corrosion inhibition performance of graphene oxide quantum dots for Q235 steel in 1 M hydrochloric acid solution

In the present work, graphene oxide quantum dots (GOQDs) prepared via electrochemical method was used as a liquid phase corrosion inhibitor. The structure and compositions of GOQDs were characterized by Fourier transform infra-red (FTIR) and X-ray photoelectron spectroscopy (XPS). The corrosion behavior of Q235 steel in 1 M hydrochloric acid solution in the absence and presence of different concentrations of GOQDs at different temperatures was investigated using weight loss and electrochemical measurements. The steel surface morphology was investigated with the implementation of XPS, scanning electron microscopy (SEM), and atomic force microscopy (AFM). It was found that the prepared GOQDs presented the best inhibition efficiency over 94%. The characterization studies revealed that prepared GOQDs contains functional groups such as carboxyl, hydroxyl, and aldehyde groups, which can spontaneously self-assembles on the metal surface to form adsorbed film, the adsorption isotherm showed that the adsorption process obeyed the Langmuir equation. The electrochemical polarization measurements demonstrated that GOQDs served as a mixed type inhibitor with the primarily inhibitive performance on anodic reaction, which is in well agreement with the adsorption free energy results.