Combining theoretical and experimental researches to insight the anti-corrosion nature of Citrus reticulata leaves extract

Abstract In recent years, natural plant extracts have received widespread attention as the novel and environment-friendly corrosion inhibitors. In this paper, we used the ultrapure water extract method to gain Citrus reticulata leaves extract (CRLE). The theoretical and experimental methods were used to explore the anti-corrosion nature of CRLE for Cu in sulfuric acid environment from multiple angles. Electrochemical experiments show that when the CRLE concentration was 500 mg/L, its anti-corrosion efficiency (η) can be as high as 97.3%. In addition, we explored the effect of soak time on the corrosion inhibition nature of CRLE. The experimental results shown that the copper electrode dip in the sulfuric acid solution containing 500 mg/L CRLE for 24 h, the η of CRLE can still reach more than 93%. Therefore, it can be shown that CRLE can form the stable barrier film on the Cu surface. In addition, the surface topography analysis results are conform to the electrochemical experimental results. The adsorption isotherm model studies manifest CRLE adsorb at the Cu interface conforms to the Langmuir monolayer adsorption. Quantum chemical calculations and molecular dynamics simulations have shown that CRLE can exhibit excellent anti-corrosion nature.