文摘
From thermodynamics and chemical bonding dynamics, we study antisite atom segregation in porous boron nitride nanotubes (BNNTs), with respect to prefect counterparts, using density functional theory. Thermodynamic considerations show that the pores are able to overcome the barrier of antisite atom segregation; determining the phenomenon is impossible or very difficult in the nanotube growth. A two-step synthesis approach is proposed for atom segregation or chemical doping. B and N atom segregations at the vacancy experience quite different chemical bonding processes, which are ascribed to the nature of inserted B and N 鈥渃lusters鈥?and exhibit different redox properties. The B atoms prefer large-scale segregation, whereas the N atoms tend to form some separate 鈥渟egregated units鈥? We propose that different structures and properties allow antisite atom segregation in BNNTs, either nonporous or porous, to offer many promising applications in new fields, such as biolabeling, purification, chemical, and biological separations.