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Environmentally friendly gamma-MnO2 hexagon-based nanoarchitectures: structural understanding and their energy-saving applications.
- Source :
-
Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2009; Vol. 15 (2), pp. 492-500. - Publication Year :
- 2009
-
Abstract
- Although about 200,000 metric tons of gamma-MnO(2) are used annually worldwide for industrial applications, the gamma-MnO(2) structure is still known to possess a highly ambiguous crystal lattice. To better understand the gamma-MnO(2) atomic structure, hexagon-based nanoarchitectures were successfully synthesized and used to elucidate its internal structure for the present work. The structural analysis results, obtained from the hexagon-based nanoarchitectures, clearly show the coexistence of akhtenskite (epsilon-MnO(2)), pyrolusite (beta-MnO(2)), and ramsdellite in the so-called gamma-MnO(2) phase and verified the heterogeneous phase assembly of the gamma-MnO(2) state, which violates the well-known "De Wolff" model and derivative models, but partially accords with Heuer's results. Furthermore, heterogeneous gamma-MnO(2) assembly was found to be a metastable structure under hydrothermal conditions, and the individual components of the heterogeneous gamma-MnO(2) system have structural similarities and a high lattice matches with pyrolusite (beta-MnO(2)). The as-obtained gamma-MnO(2) nanoarchitectures are nontoxic and environmentally friendly, and the application of such nanoarchitectures as support matrices successfully mitigates the common problems for phase-change materials of inorganic salts, such as phase separation and supercooling-effects, thereby showing prospect in energy-saving applications in future "smart-house" systems.
Details
- Language :
- English
- ISSN :
- 1521-3765
- Volume :
- 15
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Chemistry (Weinheim an der Bergstrasse, Germany)
- Publication Type :
- Academic Journal
- Accession number :
- 19034939
- Full Text :
- https://doi.org/10.1002/chem.200801814