Synthesized few-layers hexagonal boron nitride nanosheets

The hexagonal boron nitrides (BNs) with different morphologies are synthesized on a large scale by a simple route using a two-step synthetic process. The morphology of h-BN can be easily controlled by changing the heat-treatment atmosphere. The whiskers with 0.5–10 μm in diameter and 50–100 μm in length consist of few-layers nanosheets in the NH₃ gas. The BN nanosheets can be dissociated from the whiskers by ultrasonic treatment, which are less than 5 nm in thickness and even only two layers thick. The concentration and activity of N play an important role, and abundant N and higher activity are conducive for refining grain in reaction. The H₃BO₃ and C₃N₆H₆ molecules form a layer-like morphology with the interlinked planar triangle by a hydrogen-bonded structure. (paper)