Effects of Surface Functional Groups of Nanomaterials on Corrosion Inhibition Performance and Mechanisms

• • Amino-rich carbon dots (NCDs) achieve 91.2% inhibition efficiency on Q235 carbon steel in 1 mol/L HCl at 100 mg/L, outperforming thiol-rich SCDs (86.6%) and carboxyl-rich OCDs (79.0%), establishing a clear ranking for surface group selection in acid pickling formulations. • • The 12.2 percentage-point IE gap between NCDs and OCDs translates directly to reduced acid consumption and lower hydrogen embrittlement risk in industrial pickling lines, where even a 5% improvement in inhibitor performance can cut steel loss by hundreds of tons annually. • • Parallel adsorption configuration and binding energy are the controlling factors: NCDs and SCDs adsorb parallel to the steel surface, while OCDs cannot, resulting in the lowest binding energy and least dense protective film—a mechanistic threshold that dictates whether a functional group is viable for inhibitor design. • • The post-modification strategy successfully isolates surface chemistry as the sole variable while holding particle size and carbon core structure constant, providing a validated experimental protocol that eliminates the confounding effects that have historically obscured structure–property relationships in nanomaterial inhibitors.