Biomass-derived　carbon　dots　(CDs)　have　shown　significant　promise　in　protecting　carbon　steel　from　corrosion　in　acidic　solutions,　owing　to　their　eco-friendly,　renewable,　and　cost-effective　characteristics.　However,　presently　their　effectiveness　in　neutral　NaCl　solutions　remains　unclear.　Due　to　this,　this　study　has　investigated　the　corrosion　inhibition　effectiveness　of　litchi　leaf-derived　CDs　(LCDs)　and　bamboo　leaf-derived　CDs　(BCDs)　for　carbon　steel　in　NaCl　solutions.　The　LCDs　and　BCDs　were　synthesized　via　a　straightforward　one-step　hydrothermal　method　using　litchi　leaves　and　bamboo　leaves,　respectively.　The　electrochemical　tests　revealed　that　both　LCDs　and　BCDs　exhibited　limited　corrosion　inhibition　performance　in　the　3.5　wt%　NaCl　solution.　The　LCDs　achieved　a　maximum　corrosion　inhibition　efficiency　of　71.14　%　at　800　mg/L,　whereas　the　BCDs　reached　47.69　%　at　600　mg/L.　Meanwhile,　the　molecular　simulations　highlighted　the　inadequate　adsorption　capability　of　the　LCDs　and　BCDs　on　the　carbon　steel　surfaces　as　a　primary　factor　contributing　to　their　suboptimal　corrosion　inhibition　in　the　neutral　NaCl　conditions.　As　a　result,　this　study　provides　critical　insight　into　the　challenges　of　deploying　biomass-derived　CDs　for　effective　corrosion　inhibition　in　practical　applications　under　neutral　environmental　conditions.　©　2025　Elsevier　Ltd