First-Principles Calculations of the Hydrolysis Mechanism of Hexagonal Boron Nitride Nanosheets: Implications for Preventing Hydrolytic Degradation

Hexagonal boron nitride nanosheets (h-BNNSs) are an important two-dimensional material with broad industrial applications. However, the difficulty to efficiently prepare large size and high-quality h-BNNSs has been a major obstacle for the large-scale application of h-BNNS. Most preparation methods for h-BNNS are carried out in aqueous environments, and h-BNNS-based devices may be deployed in humidity. Consequently, the hydrolysis decomposition of h-BNNS plays a significant role in the fracture and the degradation of the material. Increasing the stability of h-BNNS in aqueous environment may be a promising approach to improve both the preparation efficiency and the performance of h-BNNS devices. In this work, using first-principles calculations, we conduct a thorough investigation on the detailed mechanism of the hydrolysis process of h-BNNS. We demonstrate how cracks are initiated and how they grow on different edges, and we show how the h-BNNS edge dissolves gradually via hydrolysis. On the basis of these results, we further examine the effects of functionalization on the stability of h-BNNS, and we demonstrate how to protect h-BNNS from hydrolysis using proper edge functionalization strategy.