Preparation and growth mechanism of α-Bi2O3 crystal whiskers

Abstract

Precursor of BiOCl was synthesized using BiCl3 and NaOH. Bi2O3 whiskers with high aspect ratio were prepared through reversing-titration method, i.e., dispersing BiOCl in Na2SO4, then dropped it in NaOH solution. The formation of monoclinic α-Bi2O3 crystal whiskers was characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). SEM and TEM results revealed the aspect ratios of Bi2O3 whiskers were from 10 to 40, and the morphology of α-Bi2O3 evolved from single-needle-like to multi-needle-like crystal whiskers with the increase of Na2SO4 concentration. Selected area electronic diffraction saed (SAED) patterns showed that the Bi2O3 whiskers were single crystalline grown along [210] direction. Furthermore, we discussed the mechanism of crystal growth.