Self-doped walnut green husk carbon dot inhibitor: Interfacial behavior and corrosion inhibition mechanism

• WGH CDs is a new type of self-doped amorphous graphene-like carbon dot corrosion inhibitor. • The WGH CDs possess numerous active sites and can be adsorbed parallelly on the Fe (110) plane. • WGH CDs is a type of cathodic inhibitor, mainly inhibiting the cathode hydrogen evolution reaction. • WGH CDs can interact with CRS surface through physical and chemical interaction. Walnut green husk as raw material to prepare a novel, efficient carbon dots inhibitor (WGH CDs) by hydrothermal method, and the structures and inhibition performance were determined by theoretical and experimental. The results reveal that WGH CDs are self-doped, graphene-like carbon dots with abundant functional groups on their surfaces, exhibit an amorphous structure, and contain crystalline regions. Theoretical simulations indicate that WGH CDs present multi-site adsorption capacity, film stability, and high surface coverage, which could effectively prevent the migration of corrosive particles. The weight loss method results prove that the adsorption of WGH CDs on cold rolled steel (CRS) surface in 0.10 M Cl 3 CCOOH medium follows the Langmuir adsorption isotherm, and it can interact with CRS surface through physical and chemical interaction. The inhibition efficiency can reach up to 94.27 %. The electrochemical test results show that WGH CDs is a cathode inhibitor, which mainly forestalls the generation of hydrogen ions at the cathode. It can significantly reduce the current density and effectively inhibit the electron transfer process. The surface characterization results demonstrate that it can reduce the surface roughness and increase the hydrophobicity of the CRS surface. Herein, WGH CDs have great potential as environmental inhibitors and provide a new direction for corrosion research and practical application.