Deng Hongmei, Hossenlopp Jeanne M
Department of Chemistry, Marquette University, P.O. Box 1881, Milwaukee, Wisconsin 53201-1881, USA.
J Phys Chem B. 2005 Jan 13;109(1):66-73. doi: 10.1021/jp047812s.
Nanocrystalline mixtures of Sn(II) and Sn(IV) oxide powders, potential gas sensor materials, are synthesized via a simple precipitation route using SnCl(2) as the precursor. Materials are characterized by powder X-ray diffraction, thermogravimetric analysis, UV-visible diffuse reflectance spectroscopy (DRS), and Fourier transform infrared spectroscopy. The ratio of Sn(II)/Sn(IV) in powders precipitated at room temperature, as well as the identity of the primary Sn(II) product (SnO or Sn(6)O(4)(OH)(4)), can be varied by adjusting aging time and washing procedures. The identity of the initial Sn(II) product influences the subsequent phase composition and degree of disorder in the tetragonal SnO(2) phase obtained following sintering in air. Analysis of the DRS absorption edge and long-wavelength (Urbach) absorption tail is used to determine the SnO(2) optical band gap and extent of disorder. SnO(2) obtained by heating the SnO/SnO(2) mixture at 600 or 800 degrees C has a smaller optical band gap and a broader Urbach tail than the analogous sample obtained from heating Sn(6)O(4)(OH)(4), indicating a more disordered material.
作为潜在气体传感器材料的氧化锡（II）和氧化锡（IV）粉末的纳米晶混合物，通过以SnCl₂为前驱体的简单沉淀路线合成。通过粉末X射线衍射、热重分析、紫外可见漫反射光谱（DRS）和傅里叶变换红外光谱对材料进行表征。通过调节老化时间和洗涤程序，可以改变室温下沉淀粉末中Sn（II）/Sn（IV）的比例，以及主要Sn（II）产物（SnO或Sn₆O₄(OH)₄）的特性。初始Sn（II）产物的特性会影响在空气中烧结后得到的四方相SnO₂相的后续相组成和无序程度。通过分析DRS吸收边和长波长（乌尔巴赫）吸收尾来确定SnO₂的光学带隙和无序程度。与通过加热Sn₆O₄(OH)₄得到的类似样品相比，在600或800℃下加热SnO/SnO₂混合物得到的SnO₂具有更小的光学带隙和更宽的乌尔巴赫尾，表明材料的无序程度更高。
