Comprehensive analysis of the corrosion inhibition effect of Houttuynia Cordata extract: experimental and theoretical research

Background Due to the low toxicity and easy decomposition of green plant extracts, they are gradually replacing traditional corrosion inhibitors. Generally, plant extracts have low corrosion inhibition efficiency in corrosive media and are difficult to exert corrosion inhibition effects. Therefore, it is urgent to find efficient plant resources as corrosion inhibitors. Houttuynia cordata (HC) was used as the raw material and the corrosion inhibition performance and mechanism on Q235 were studied in 1.0 mol/L HCl solution. Methods The corrosion inhibition performance and mechanism were verified through weight loss and electrochemical experiments. SEM + EDS, ATR-IR and XPS were used to detect and analyse the protective film formed on the surface of Q235 after weight loss. DFT demonstrated the adsorption sites and reaction activity of the corrosion inhibitor, and MD further verified the corrosion inhibition mechanism. Significant Findings HC could spontaneously adsorb on the surface of Q235 and formed a stable protective film. With the temperature increased, the corrosion inhibition efficiency decreased gradually. At 293 K and 1.0 g/L, the corrosion inhibition efficiency could reach 96.97% in weight loss experiment, HC could simultaneously inhibit the anodic and cathodic reactions in 1.0 mol/L HCl solution, and followed Langmuir adsorption isotherm.