Environmentally friendly, scalable exfoliation for few-layered hexagonal boron nitride nanosheets (BNNSs) by multi-time thermal expansion based on released gases

Abstract

An environmentally friendly, facile scalable exfoliation route for two-dimensional hexagonal boron nitride (h-BN) would be beneficial for several potential applications. In this work, we invented a competitive exfoliation route for high-yield boron nitride nanosheets (BNNSs) on the basis of the above mentioned targets. By means of releasing gases derived from the decomposition of oxalic acid pre-impregnated in the interlayers of bulk h-BN, scalable exfoliation was achieved using multi-time thermal expansion. The as-exfoliated BNNSs with an intact inplane structure had a thickness of 3–5 nm and an approximately 13.6% output. Furthermore, the high-quality BNNSs exhibited better dispersion in base oil, which was conducive to being applied as an additive in oil, owing to the superlubricating properties of the two-dimensional layered nanosheets.