Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

High Resolution Electron Microscopy Study of Nanocubes and Polyhedral Nanocrystals of Cerium(IV) Oxide

Full text
Author(s):
Cordeiro, Marco A. L. [1] ; Weng, Weihao [2] ; Stroppa, Daniel G. [3] ; Kiely, Christopher J. [2] ; Leite, Edson R. [4]
Total Authors: 5
Affiliation:
[1] Univ Fed Sao Carlos, Dept Mat Sci & Engn, BR-13565905 Sao Carlos, SP - Brazil
[2] Lehigh Univ, Dept Mat Sci & Engn, Bethlehem, PA 18015 - USA
[3] Brazilian Synchrotron Light Lab, BR-13083970 Campinas, SP - Brazil
[4] Univ Fed Sao Carlos, Dept Chem, BR-13565905 Sao Carlos, SP - Brazil
Total Affiliations: 4
Document type: Journal article
Source: CHEMISTRY OF MATERIALS; v. 25, n. 10, p. 2028-2034, MAY 28 2013.
Web of Science Citations: 20
Abstract

In this research, high resolution transmission electron microscopy (HRTEM) and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) studies of ceria(IV) oxide CeO2 nanocrystals (NCs) synthesized by a hydrothermal/two phase process were conducted. The synthesis route affords the possibility of controlling the shape of the CeO2 NCs by changing the oleic acid/cerium ({[}OLA]/{[}Ce3+]) ratio. At a relatively low {[}OLA]/{[}Ce3+] ratio of 4, a polyhedral NC morphology was obtained with [111] and [200] termination facets. Increasing the {[}OLA]/{[}Ce3+] ratio to 8, while maintaining a constant reaction time and temperature during the synthesis, truncated cube-like CeO2 NCs with [200], [220], and [111] termination facets was generated. These morphologies were identified by HRTEM and HAADF-STEM characterization. Fourier transform infrared (FT-IR) analysis and thermogravimetric analysis (TGA) confirm the presence of chemically bonded oleic acid (OLA) on the CeO2 NC surface. It indicates that there is a relationship between the bonded OLA and the shape of the NC. Additionally, the identification of concave surfaces on [200] facets by HAADF-STEM characterization suggests that the formation of the cube-like CeO2 morphology is a multiple step mechanism. On the basis of these observations new growth mechanisms for the CeO2 morphology variants are proposed. (AU)