Synthesis and Characterization of Cubic Bismuth Zinc Niobate Pyrochlore (Bi_(1.5)ZnNb_(1.5)O_7) Nanotubes

摘要

Cubic bismuth zinc niobate pyrochlore, Bi_(1.5)ZnNb_(1.5)O_7, (BZN) nanotubes (diameter ～ 200 nm; wall thickness ~ 25 nm) were synthesized by sol-gel technique using nanochannel porous anodic aluminum oxide (AAO) templates and were characterized by different techniques. X-ray diffraction (XRD) and selected-area electron diffraction (SAED) investigations demonstrated that postannealed (550℃ for 1 h) BZN nanotubes exhibit a polycrystalline cubic-pyrochlore-structure with highly preferential crystal growth along (222) orientation. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) investigations confirmed the smooth wall morphologies and well-defined diameters corresponding to the pores diameter of the applied template. High resolution TEM (HRTEM) analysis demonstrated that as obtained BZN nanotubes made up of nanoparticles (10-15 nm) which are randomly aligned in the nanotubes. Energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the formation of stoichiometric Bi_(1.5)ZnNb_(1.5)O_7. The possible formation mechanism of BZN nanotubes was discussed.