Thermal conductivity of hydrogenated h-BN nanosheets: a reactive force field study

Thermal conductivity of hydrogenated hexagonal boron nitride (h-BN) nanosheets was investigated using molecular dynamics simulation method. A newly parameterized reactive force field (ReaxFF) for hydrogen and h-BN interactions was used. ReaxFF was used due to its higher accuracy compared to other simpler interatomic potentials. Accurate thickness selection of a monolayer h-BN nanosheet has been shown to produce high thermal conductivity values for pristine armchair and zigzag nanosheets. It was further found that hydrogenation diminishes thermal conductivity of hydrogenated h-BN nanosheets. This reduction in thermal conductivity was due to the occurrence of sp(2) to sp(3) bonding transition when hydrogen atoms were placed on top of B and N atoms. The increase in temperature was also found to diminish thermal conductivity due to the occurrence of phonon-phonon scattering at higher temperatures. N-vacancy defect has then been shown to exhibit lower thermal conductivity compared to B-vacancy defect. Furthermore, the removal of more atoms contributes to higher decline in thermal conductivity. However, vacancy defect constructed along vertical direction provides the highest reduction in thermal conductivity. It is expected that this work provides useful insights for the design of an effective hydrogen storage system using these novel h-BN nanosheets.

Automated summary

The thermal conductivity of hydrogenated h-BN nanosheets was investigated using molecular dynamics simulations. A newly parameterized reactive force field (ReaxFF) was used to accurately model the interactions between hydrogen and h-BN. It was found that hydrogenation reduces the thermal conductivity due to a change in the bonding structure. Additionally, both increased temperature and the presence of vacancy defects were found to further decrease the thermal conductivity. These findings provide insights for the design of hydrogen storage systems using h-BN nanosheets.