N, S, P self-doped carbon quantum dots derived from orange peel as green corrosion inhibitors for 7A04 aluminum alloy

This research employed biomass orange peel as a precursor to synthesize N, S, P heteroatom self-doped carbon quantum dots (N, S, P-BCQDs) via hydrothermal treatment for use as corrosion inhibitors. The inhibitory effectiveness of N, S, P-BCQDs on 7A04 aluminum alloy in HCl solution was evaluated by electrochemical analysis, weight loss test, surface characterization, and density functional theory (DFT) simulations. The findings demonstrate that N, S, P-BCQDs act as mixed-type inhibitors, predominantly suppressing cathodic reactions. The corrosion inhibition efficiencies increase with concentration, reaching a maximum of 93.07% at 150 mg L −1 . Furthermore, the higher the concentration of N, S, P-BCQDs, the slower the decrease in corrosion inhibition efficiency with the extension of immersion time. Analysis of the corrosion inhibition mechanism indicates that N, S, P-BCQDs can spontaneously form a thick and stable protective film on the surface of aluminum alloys through multiple interactions, including physical adsorption, chemical adsorption, aggregation effects and chelation reactions. This film elevates the energy barrier for corrosion reactions, effectively suppressing the corrosion process. This work reveals the significant potential of biomass-derived heteroatom self-doped carbon quantum dots for advanced anticorrosion applications.