Observation of the Reversible Phase-Transformation of -Mn2O3 Nanocrystals during the Catalytic Combustion of M
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- 作者：Yi-Fan Han ; Kanaparthi Ramesh ; Luwei Chen ; Effendi Widjaja ; Srilakshmi Chilukoti ; Fengxi Chen
- 刊名：Journal of Physical Chemistry C
- 出版年：2007
- 出版时间：February 22, 2007
- 年：2007
- 卷：111
- 期：7
- 页码：2830 - 2833
- 全文大小：93K
- 年卷期：v.111,no.7(February 22, 2007)
- ISSN：1932-7455
文摘
Real-time in situ Raman spectroscopy is used to probe the near-surface structure of 
-Mn2O3 nanocrystalsduring methane combustion for the first time. A surface phase-transformation from -Mn2O3 to Mn3O4-likespecies, as evidenced by the formation of a single band at 648 cm-1, was observed only at or above 400 
Cin the presence of pure He or in the mixture of O2 + CH4. This modification is probably due to the loss oflattice oxygen at high temperatures that leads to the surface reconstruction. Very interestingly, a reversiblephase-transformation was observed with decreasing the temperature to 25 C. The phase-change at the near-surface is suggested to be associated with the activating C-H bond of methane.
-Mn2O3 nanocrystalsduring methane combustion for the first time. A surface phase-transformation from -Mn2O3 to Mn3O4-likespecies, as evidenced by the formation of a single band at 648 cm-1, was observed only at or above 400 Cin the presence of pure He or in the mixture of O2 + CH4. This modification is probably due to the loss oflattice oxygen at high temperatures that leads to the surface reconstruction. Very interestingly, a reversiblephase-transformation was observed with decreasing the temperature to 25 C. The phase-change at the near-surface is suggested to be associated with the activating C-H bond of methane.