A simple method to synthesize single-crystalline β-wollastonite nanowires

The single-crystalline beta-wollastonite (beta-CaSiO3) nanowires were prepared via a simple hydrothermal method, in the absence of any template or surfactant using cheap and simple inorganic salts as raw materials. Xonotlite [Ca-6(Si6O17)(OH)(2)] nanowires were first obtained after hydrothermal treatment at a lower temperature of 200 degrees C for 24 h, and after being calcinated at 800 degrees C for 2 h, xonotlite nanowires completely transformed into beta-wollastonite nanowires and the wire-like structure was preserved. The synthesized beta-wollastonite nanowires had a diameter of 10-30 nm, and a length up to tens of micrometers, and the single-crystalline monoclinic parawollastonite structured beta-wollastonite was identified by XRD with the space group of P2(1/a) and cell constants of a = 15.42 angstrom, b = 7.325 angstrom, c = 7.069 angstrom and beta = 95.38 degrees. A possible growth mechanism of beta-wollastonite nanowires was also proposed. The advantages of this method for the nanowire synthesis lie in the high yield, low temperature and mild reaction conditions, which will allow large-scale production at low cost. (c) 2007 Elsevier B.V. All rights reserved.