Reaction Pathway Analysis of B/Li<sub>2</sub>O in a Li–B–O System for Boron Nitride Nanotube Growth
Kai Zhang, Pan Xue, Jianghua Wu, Liyun Wu, Nanyang Wang, Tao Xu, Kaiping Zhu, Jun Pu, Qiulong Li, Yu Deng, Yagang Yao, Jin Zhang
Abstract
Compared to other synthetic methods, the synthesis of boron nitride nanotubes (BNNTs) by the boron oxide chemical vapor deposition (BOCVD) method can balance the purity and quality of the product nanotubes. However, due to the solid reaction characteristics of boron monomers, the closed reaction system, and the synthesis temperature of over 1000 °C, growth studies of BNNTs have been in a dilemma. To this end, simultaneous thermal analysis combined with multi-atmosphere annealing experiments at corresponding temperatures is used to study the inorganic solid-state reaction of the classical BOCVD precursor B/Li 2 O in real time and confirmed by experimental results that lithium borate is the actual active component and catalyst. Further experiments reveal that the growth process of BNNTs and lithium borate not only consumes less of the precursor and ammonia but is also flexible in its configuration, showing exceptional efficiency and reactivity. Lastly, experiments have shown that the structure and activity of borate are equally applicable to alkali metals, alkaline earth metal, and transition metals.