A New Method of Synthesizing Black Birnessite Nanoparticles: From Brown to Black Birnessite with Nanostructures

Authors

Shizhi Qian, Old Dominion UniversityFollow
Marcos A. Cheney, University of Maryland Eastern ShoreFollow
Pradip K. Bhowmik, University of Nevada, Las VegasFollow
Sang W. Joo, Yeungnam UniversityFollow
Wensheng Hou, Chongqing University
Joseph M. Okoh, University of Maryland Eastern Shore

Document Type

Article

Publication Date

2008

Publication Title

Journal of Nanomaterials

Volume

2008

Issue

1

First page number:

763706

Last page number:

763706

Abstract

A new method for preparing black birnessite nanoparticles is introduced. The initial synthesis process resembles the classical McKenzie method of preparing brown birnessite except for slower cooling and closing the system from the ambient air. Subsequent process, including wet-aging at 7◦C for 48 hours, overnight freezing, and lyophilization, is shown to convert the brown birnessite into black birnessite with complex nanomorphology with folded sheets and spirals. Characterization of the product is performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA), and N2 adsorption (BET) techniques. Wet-aging and lyophilization times are shown to affect the architecture of the product. XRD patterns show a single phase corresponding to a semicrystalline birnessite-based manganese oxide. TEM studies suggest its fibrous and petal-like structures. The HRTEM images at 5 and 10 nm length scales reveal the fibrils in folding sheets and also show filamentary breaks. The BET surface area of this nanomaterial was found to be 10.6m2/g. The TGA measurement demonstrated that it possessed an excellent thermal stability up to 400◦C. Layerstructured black birnessite nanomaterial containing sheets, spirals, and filamentary breaks can be produced at low temperature (−49◦C) from brown birnessite without the use of cross-linking reagents.

Keywords

Crystallography; Layer structure (Solids); Manganese oxides; Microstructure; Nanoparticles

Disciplines

Materials Science and Engineering | Mechanical Engineering | Mineral Physics | Nanoscience and Nanotechnology

Language

English

Creative Commons License

This work is licensed under a Creative Commons Attribution 3.0 License.

Repository Citation

Qian, S., Cheney, M. A., Bhowmik, P. K., Joo, S. W., Hou, W., Okoh, J. M. (2008). A New Method of Synthesizing Black Birnessite Nanoparticles: From Brown to Black Birnessite with Nanostructures. Journal of Nanomaterials, 2008(1), 763706-763706.
https://digitalscholarship.unlv.edu/me_fac_articles/262