An effective corrosion inhibitor of N doped carbon dots for Q235 steel in 1 M HCl solution

N doped carbon dots (N-CDs) were prepared by hydrothermal method in methacrylic acid and n -butylamine precursors. The inhibition behavior of N-CDs on Q235 steel in hydrochloric acid environment was discussed via weight loss test, surface characterizations and electrochemistry measurements. Results showed that the as-prepared N-CDs could effectively protect Q235 steel and the inhibition efficiency reached up to 94.96% at 200 mg/L of N-CDs. In the meantime, the impedance modulus was greatly enhanced and the corrosion current density was reduced by one order of magnitude after the addition of N-CDs. Moreover, it could adhere to the steel surface by diffusion and agglomeration effect, resulting in the formation of adsorption film on steel surface. The adsorption mechanism of N-CDs almost complied with the Langmuir adsorption model, containing chemical and physical adsorptions.