Insight into the anti-corrosion mechanism of Chinese mahonia leaves as a green and bio-degradable against copper corrosion in sulfuric acid medium

Background: Metal corrosion not only leads to significant economic losses for the country but also poses a considerable threat to human safety. The majority of corrosion inhibitors available in the market today fail to meet the demand of industrial production for green and sustainable development. Therefore, it is the pursuit of numerous researchers to find efficient, eco-friendly and low-cost methods for metal protection.Methods: In this work, the information on the main components in extracts of Chinese mahonia leave (MLE) was determined by liquid chromatography-mass spectrometry (LC-MS). The functional groups of MLE were investigated using Fourier transform infrared spectroscopy (ART-FTIR). X-ray electron spectroscopy (XPS) was selected to detect bonding information between MLE and the surface of copper. The mechanism of the anticorrosion in the Cu/H2SO4 system has been explored by theoretical calculation and electrochemical measurement.Significant findings: The electrochemical results showed that MLE could prevent corrosion of copper in the H2SO4 system, and the inhibition efficiency (IE) was 91% at 300 mg/L, MLE predominantly forms a protective film on the copper surface by employing both weak interactions (electrostatic adsorption) and strong interactions (chemical coordination). These interactions effectively isolate the copper substrate from the corrosive medium, resulting in a reduction in the corrosion rate. Combining molecular dynamics simulations with theoretical calculations, we have further confirmed that the N, O, and other heteroatoms in MLE molecules play a crucial role in their corrosion inhibition performance.