Boron Nitride Nanotube and Nanosheet Synthesis by Flash Joule Heating

Boron nitride nanotubes (BNNTs) and boron nitride nanosheets (BNNSs), known as structural analogs of carbon nanotubes (CNTs) and graphene, respectively, have garnered significant interest due to their outstanding inherent properties and broad applications. However, the rapid synthesis of these materials with high yield and quality poses a challenge, hindering their practical application advancements. In this study, we report the synthesis of highly crystalline BNNTs and BNNSs through a solid-state catalytic flash Joule heating (FJH) method, using ammonia borane as the precursor. The catalytic growth process was achieved under atmospheric conditions at easily attained FJH temperatures (~1500 °C) within seconds. By adjusting the reaction temperature and variety of catalysts, the selectivity to BNNTs can reach ~30% of the total product composition. Furthermore, the nucleated growth of BNNT on iron(0) is mediated by the introduction of carbon and sulfur. This study demonstrates a convenient and scalable synthesis pathway for BNNTs and BNNSs and provides critical insights into the mechanism of rapid synthesis techniques enabled by electrical heating.