Engineering alkyl-functionalized carbon dots for robust high-temperature acidic protection and real-time optical corrosion tracking

Conventional hydrophilic carbon dots (CDs) suffer from a critical bottleneck in high-temperature acidizing applications, i.e., drastic performance degradation due to thermal desorption. Herein, we overcome this limitation by designing a long-chain alkyl-functionalized carbon dot (CDs-C12) that synergistically integrates high-temperature corrosion protection with real-time corrosion monitoring. The hydrophobic modification not only endows CDs-C12 with exceptional thermal stability but also promotes the formation of a dense, self-assembled protective film on N80 steel. As a result, CDs-C12 achieves an outstanding inhibition efficiency of 99.36% in 1 M HCl at 90 °C—far outperforming unmodified CDs, which lose efficacy under the same conditions. Beyond protection, the material retains the intrinsic fluorescence of carbon dots, enabling selective recognition of Fe3+/Fe2+ ions via static quenching, thereby allowing non-destructive, real-time optical tracking of corrosion progression. This dual functionality, i.e., uniting robust high-temperature inhibition with in situ self-reporting capability, positions CDs-C12 as a smart, multifunctional additive for corrosion management in harsh oilfield environments.