Computational study of boron nitride nanotube synthesis: how catalyst morphology stabilizes the boron nitride bond

TL;DR

This study uses first-principles calculations to explore how catalyst surface morphology influences boron nitride nanotube synthesis, highlighting the stabilizing role of step edges in promoting BN formation over B2 on iron catalysts.

Contribution

It reveals that atomic step edges on catalysts stabilize BN molecules, providing insights for improving BN nanotube growth efficiency compared to carbon nanotubes.

Findings

Step edges stabilize BN molecules on iron catalysts.

B2 formation hinders BN nanotube growth.

Atomic morphology influences catalytic activity.

Abstract

In an attempt to understand why catalytic methods for the growth of boron nitride nanotubes work much worse than for their carbon counterparts, we use first-principles calculations to study the energetics of elemental reactions forming N2, B2 and BN molecules on an iron catalyst. We observe that in the case of these small molecules, the catalytic activity is hindered by the formation of B2 on the iron surface. We also observe that the local morphology of a step edge present in our nanoparticle model stabilizes the boron nitride molecule with respect to B2 due to the ability of the step edge to offer sites with different coordination simultaneously for nitrogen and boron. Our results emphasize the importance of atomic steps for a high yield chemical vapor deposition growth of BN nanotubes and may outline new directions for improving the efficiency of the method.