Title

Synthesis and Characterization of inorganic double helices of cryptomelane nanomaterials

Document Type

Article

Publication Date

10-15-2006

Publication Title

Colloids and Surfaces A: Physocpchemical and Engineering Aspects

Publisher

Elsevier

Volume

289

Issue

1-3

First page number:

185

Last page number:

192

Abstract

For the past century, researchers have invested great efforts in the synthesis of materials with various shapes and sizes. We have developed a method to prepare what appear to be inorganic double helices of cryptomelane nanomaterial with the highest surface area ever reported for this class of materials. The synthesis is based on the oxidation of MnSO4 by permanganate ion in acidic conditions at 65 °C and wet-aging at 7 °C for 48 h and then lyophilized for 8 days. The particle size, crystal structure, and properties of this nanomaterial have been studied by X-ray diffraction (XRD), high-resolution electron microscopy (HRTEM), thermogravimetric analysis (TGA), and N2 adsorption (BET) analysis. The wet-aging time, and exposure to air during reaction affect the size of the crystals formed in the final product. The XRD pattern showed a single phase corresponding to the pure cryptomelane-type manganese oxide. TEM studies suggest a fibrous structure. In the HRTEM images, however, at 5 nm length scale, spiraling along the radial direction is clearly observed suggesting helices. The BET surface area of this nanomaterial was found to be 150 m2/g which is higher than the previous reported surface area (130 m2/g) [J.C. Villegas, L.J. Garces, S. Gomes, J.P. Durand, S.L. Suib Chem. Mater. 17 (2005) 1910] for this class of materials. The TGA measurement demonstrated that it possessed an excellent thermal stability up to 400 °C. We show here that inorganic helices of cryptomelane nanomaterial may be produced at low temperature, without the use of template or cross-linking reagents.

Keywords

Inorganic double helices; Manganese compounds; Manganese dioxide; Manganese oxides; Nanostructured materials; Nanostructures; Surfaces — Areas and volumes; Synthesis; Transmission electron microscopes

Disciplines

Chemistry | Nanoscience and Nanotechnology

Language

English

Permissions

Use Find in Your Library, contact the author, or use interlibrary loan to garner a copy of the article. Publisher copyright policy allows author to archive post-print (author’s final manuscript). When post-print is available or publisher policy changes, the article will be deposited

Identifier

DOI: http://dx.doi.org/10.1016/j.colsurfa.2006.04.042

Publisher Citation

Marcos A. Cheney, Nancy R. Birkner, Longzhou Ma, Thomas Hartmann, Pradip K. Bhowmik, Vernon F. Hodge, Spencer M. Steinberg, Synthesis and characterization of inorganic double helices of cryptomelane nanomaterials, Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 289, Issues 1–3, 15 October 2006, Pages 185-192, ISSN 0927-7757, 10.1016/j.colsurfa.2006.04.042.