Chemical exfoliating of boron nitride into edge-hydroxylated nanosheets

The edge-hydroxylated boron nitride nanosheets (BNNS) not only has excellent thermal stability, electrical properties, but also has high specific surface area, good dispersibility and compatibility. In this paper, edge-hydroxylated BNNS was obtained by stripping hexagonal boron nitride (h-BN) using wet chemical reaction method. The hydroxylated structure of the surface and formation mechanism of BNNS were analyzed, and the optimal controlled conditions were explored by orthogonal test. The results showed that the content of N element in the center of the BNNS (46.44 at. %) is significantly higher than that of B element in the edge of the sheets (33.10 at. %), and the content of O element in the edge of the sheets is nearly 30% higher than that in the center. It indicates that the edge of the BNNS introduces more oxygen than h-BN, the nitrogen atoms at the edge are replaced by oxygen atoms to achieve hydroxylation. When the mass ratio of h-BN and potassium permanganate is 1 g: 5 g, the reaction time is 9 h, and the reaction temperature is 60 °C, the obtained nanosheets have the best hydroxylation and good stripping effect. The average lateral size of the exfoliated nanosheets is 123 nm and only about three layers. Graphical Abstract