Low temperature, organic-free synthesis of Ba₃B₆O₉(OH)₆nanorods and β-BaB₂O₄nanospindles

Abstract

Using a low temperature, organic-free hydrothermal technique, single-crystalline barium polyborate Ba3B6O9(OH)6 (BBOH) nanorods were synthesized. It was found that β-BaB2O4 (BBO) nanospindles can be achieved by annealing the BBOH nanorods at a relatively low temperature of 810 °C. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques were used to characterize these nanomaterials. The formation mechanisms are discussed in conjunction with the crystallographic characteristics and surface energy of the BBOH nanorods and BBO nanospindles. UV-vis absorption spectra demonstrated that both BBOH nanorods and BBO nanospindles are transparent from the ultraviolet to the visible regions.