Super-anticorrosion epoxy nanocomposites prepared with P-doped carbon dots functionalized large-size boron nitride nanosheets

Large-size ultrathin 2D nanosheets show huge advantages in improving the barrier and anticorrosion properties of organic coatings. However, the irreversible agglomeration of large-size nanosheets has become a key scientific issue restricting their practical applications. Herein the in situ phosphorus-doped carbon dots (PCDs) are synthesized and decorated on large-size boron nitride nanosheets (BNNSs) matrix, to empower excellent dispersion of BNNSs (stable for a few weeks) and superlative nanosheet-matrix bonding with matrix. When served as the functional fillers for epoxy (EP) coatings, the resultant PCD@BNNS/EP composite coating shows greatly enhanced corrosion resistance due to the long-range ordered self-alignment of large-size PCD@BNNSs and strong interfacial bind with coating matrix. Typically, after 5 weeks of exposure in 3.5 wt% NaCl(aq), the coating resistance of the PCD@BNNS/EP composite coating maintained 6.3 × 109 O cm2, 2 ∼ 3 orders of magnitude higher than those of unmodified BNNS/EP composite (8.0 × 107 O cm2) and blank (4.2 × 106 O cm2) coatings, revealing exceptional long-term anticorrosion performance. The anticorrosion mechanism was unlocked in detail by the chemical reactions at the coating-metal interfaces, owing to the arrested incursion of aggressive species through the multi-effect synergies of superior shielding property and passivation function by the intercalated large-size and self-aligned PCD@BNNSs. Our work introduces a unique binary hybrid material system to construct high-performance coatings for future marine and aviation protection.