Exfoliation of hexagonal boron nitride nanosheets in low-modulus concentrated alkali silicate pastes

We herein demonstrated the exfoliation of hexagonal boron nitride (h-BN) into nanosheets (BNNSs) by using concentrated low-modulus water glass (WG, SiO2/Na2O ratio = 1.6) as high viscosity exfoliating medium. The process led to BNNSs yield of nearly 30%. As the sheared suspension was neutralized with HCl, BNNSs with lateral size of approximately 250 nm and narrow size distribution, were found to align into perfectly parallel rows. High-resolution transmission electron microscopy (HR-TEM) analysis confirmed how WG preserved the integrity of the exfoliated BNNS in comparison with an analogous route with sole hydroxide, resulting in a high amount of BNNSs with undamaged structure. (C) 2021 Published by Elsevier B.V.

Automated summary

In this study, hexagonal boron nitride (h-BN) was successfully exfoliated into nanosheets using concentrated low-modulus water glass, resulting in a yield of nearly 30% BNNSs. The BNNSs obtained had lateral sizes of approximately 250 nm and narrow size distribution, aligning into parallel rows. High-resolution transmission electron microscopy (HR-TEM) analysis confirmed the integrity of exfoliated BNNSs preserved by water glass, leading to a high amount of undamaged structure BNNSs.