H-BN nanosheets obtained by mechanochemical processes and its application in lamellar hybrid with graphene oxide

Nowadays, hexagonal boron nitride nanosheets (h-BNNS) have shown promising results among 2D nanomaterials. A great effort has been made in recent years to obtain h-BNNS with a high-yield process to enable its large-scale application in industrial plants. In this work, we developed a mechanochemical method for obtaining h-BN nanosheets assisted by NaOH aqueous solution as process aid and aimed the ideal balance between yield, quality and process sustainability. Images obtained by transmission electron microscope suggested a great exfoliation of the h-BNNS in the range of 12-38 layers observed for well dispersed nanosheets. The macroscopic stability study, the polydispersity index, hydrodynamic diameter, and Zeta potential measurements suggested that material prepared in autoclave and ball milling followed by tip sonication process at 40 °C (h-BNNS-T40) could be considered the most promising material. The process used in this case reached a yield of about 37% of nanosheets with an optimal balance between quality and practicality. A hybrid lamellar material was also prepared by drop-casting and dip-coating techniques. An increase on thermal stability in oxidizing atmosphere was observed with respect to the pure graphene oxide (GO). Fourier transformation infrared spectroscopy and RAMAN suggested the presence of chemical interactions between h-BNNS and GO in the hybrid. This fact supports the interest of extending the study of this hybrid (which has an easy preparation method) to further explore its applicability.