Abstract: Carbon dots (CDs) exhibit significant potential for inhibiting equipment corrosion and scaling in desalination and seawater cooling systems. However, the anti-scaling or anti-corrosion dual functionalities of biomass-derived CDs have rarely been explored, and the structure-property relationships remain poorly understood due to structural complexity. Herein, we propose an oxygen functional group regulation strategy to elucidate the structure-performance relationship of camellia oleifera shell-derived CDs for dual anti-scaling and anti-corrosion applications. Multiscale characterization reveals that these CDs feature N/O self-doping and oxygen-rich surface functional groups, and identifies the critical roles of functional groups (e.g., -OH, -COOH, -CH₃O, and -CHO) in modulating CDs’ performance. The active sites of CDs are primarily localized on C atoms adjacent to N/O-doped regions. These functional groups enhance CDs stability without altering the active site distribution, while simultaneously optimizing local charge density and adsorption capacity. CDs show 91.35 % corrosion inhibition on steel at 30 °C (240 mg L^-1) and 92.71 % scale inhibition against CaCO₃ at 60 °C after 9 h. Notably, CDs substituted with -COOH may offer the best anticorrosion performance, while those with -OH groups may be more effective in scale inhibition.

Key words: Camellia oleifera shells (COS), Carbon dots (CDs), Corrosion inhibition, CaCO₃ scale inhibition, Molecular dynamics simulation