Science China Chemistry

, Volume 55, Issue 11, pp 2346–2352

Thermal transformation of δ-MnO2 nanoflowers studied by in-situ TEM

Articles Special Topic Growth Mechanism of Nanostructures

DOI: 10.1007/s11426-012-4688-5

Cite this article as:
Sun, Y., Liu, Y., Truong, T.T. et al. Sci. China Chem. (2012) 55: 2346. doi:10.1007/s11426-012-4688-5

Abstract

In-situ transmission electron microscopy in combination with a heating stage has been employed to real-time monitor variations of δ-phase MnO2 nanoflowers in terms of their morphology and crystalline structures upon thermal annealing at elevated temperatures up to ∼665 °C. High-temperature annealing drives the diffusion of the small δ-MnO2 nanocrystallites within short distances less than 15 nm and the fusion of the adjacent δ-MnO2 nanocrystallites, leading to the formation of larger crystalline domains including highly crystalline nanorods. The annealed nanoflowers remain their overall flower-like morphology while they are converted to α-MnO2. The preferred transformation of the δ-MnO2 to the α-MnO2 can be ascribed to the close lattice spacing of most crystalline lattices between δ-MnO2 and α-MnO2, that might lead to a possible epitaxial growth of α-MnO2 lattices on the δ-MnO2 lattices during the thermal annealing process.

Keywords

δ-MnO2 nanoflowersα-MnO2thermal annealingin-situ TEMmechanism study

Supplementary material

11426_2012_4688_MOESM1_ESM.pdf (406 kb)
Supplementary material, approximately 405 KB.

Copyright information

© Science China Press and Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  1. 1.Center for Nanoscale MaterialsArgonne National LaboratoryArgonneUSA
  2. 2.X-Ray Science DivisionArgonne National LaboratoryArgonneUSA