Insight into the liquid-phase exfoliation to prepare BN nanosheets

Boron nitride nanosheets (BNNSs) were prepared by metal-hydroxyl ion assisted liquid exfoliation from commercial hexagonal boron nitride (h-BN) powder. Aqueous solution of LiOH, NaOH and KOH were selected to examine the relationship between the nature of ions and the exfoliation efficiency. It was found that the yield of BNNSs were improved with the decrease of the size of cations and can be up to 12.75% in the LiOH aqueous solution. Cations with smaller radius were more easily absorbed on the outmost surface of bulk h-BN; and further inserted into the interlayer space, which is a key step for efficient preparation of BNNSs in alkaline aqueous solution. Furthermore, the morphology and structure of the as-prepared BNNSs were determined by multiple characterizations. It was also revealed that the finally obtained BNNSs are high-quality few-layer and not functionalized during exfoliation. (C) 2020 Elsevier B.V. All rights reserved.