Inheriting morphology and photoluminescence properties of MgO nanoplates
- PDF / 161,041 Bytes
- 5 Pages / 585 x 783 pts Page_size
- 4 Downloads / 151 Views
This work reports on a new morphology-inheriting methodology to MgO nanoplates. Precursor of Mg(OH)2 nanoplates was synthesized by a solvothermal method and showed a hexagonal shape. The morphological features of Mg(OH)2 nanoplates were retained to the resulting MgO nanoplates using a programmed heating process. MgO nanoplates showed highly hydroxylated surfaces. Upon excitation, the interactions between hydroxyl groups and surface O2−4c and O2−3c species gave rise to a dominant ultraviolet emission at 415 nm.
I. INTRODUCTION
MgO is among the very important metal oxides that have practical application in refractory material industries, paintings, and superconductors,1–4 or as substrates for thin film growth.5,6 As is common to many other alkaline-earth oxides, low-coordinate oxide ions, hydroxyl groups, and point defects on MgO surfaces can act as the chemically reactive sites for chemisorption and destructive adsorptions of various pollutants for environmental cleaning purposes. It is well known that most of the important chemical reactions and property tailoring for technological uses occur on the surfaces or within the interface regime. To evaluate the dominant roles that highly reactive MgO plays in catalyzing chemical reactions, it appears very important to understand the chemical nature associated with the surface structures of MgO. Photoluminescence spectroscopy has been proved to be a very useful tool in probing the surface features.7,8 Bailly et al.9 investigated the interaction of water and methanol with MgO samples by in situ photoluminescence measurements. The correlation between the optical properties and grain size (or surface area) of MgO nanocubes has been established by Stankic et al.10 Basically, the properties and applications of nanocrystals are strongly dependent on the particle dimension, morphology, and surface states. Yu et al.11 synthesized porous magnesium hydroxide and its oxide nanoplates. Compared with other MgO nanostructures including MgO nanorods,12 nanobelts,13 or nanosheets,14 MgO nanoplates have a large abundance of thermodynamically
a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2007.0142 908
J. Mater. Res., Vol. 22, No. 4, Apr 2007 http://journals.cambridge.org Downloaded: 18 Mar 2015
stable [100] faces and well-defined corners and edges, which provide a model system for understanding in detail the nature and chemically reactive centers on the surfaces. However, knowledge about the surface features of MgO nanoplates is rather scarce, probably due to the difficulty in synthesizing MgO nanoplates with welldefined surface structures. In this article, we report on the synthesis of MgO nanoplates of well-defined surface structures by a newly developed morphology-inheriting technique. Photoluminescence properties associated with the surface hydroxyls and defects of MgO nanoplates have also been determined.
II. EXPERIMENTAL
Mg(OH)2 nanocrystalline samples were prepared by a solvothermal method in which Mg(Ac)2· 4H2O and NaOH were used
Data Loading...
