Highly Ordered Boron Nitride Nanotube Arrays with Controllable Texture from Ammonia Borane by Template‐Aided Vapor‐Phase Pyrolysis

An efficient approach for the preparation of good-quality boron nitride nanotubes (BNNTs) is developed. BNNTs with specific texture were prepared from ammonia borane (BH3NH3) by vapor-phase pyrolysis with the aid of a template in two independent temperature-controlled furnaces. Two kinds of BNNTs, 200–300 nm wide ×60 μm long and 70–80 nm wide ×40 μm long, were produced after removal of the templates. The as-produced BNNTs were heated at different temperatures in the range of 1300–1700°C in NH3. FT-IR and XPS results confirmed the formation of BN from BH3NH3. Ordered arrays of BNNTs without cracks on the surface were seen using microstructural observations. The diameter and length of the BNNTs are controlled using templates with different pore sizes and thickness. The wall thickness of the nanotubes was increased by increasing the number of deposition cycles. The crystallinity of the BNNTs was improved by heating at a high temperature (1700°C) in NH3