Synthesis of ordered mesoporous Fe3O4 and γ-Fe2O3 with crystalline walls using post-template reduction/oxidation
Synthesis of ordered mesoporous Fe3O4 and γ-Fe2O3 with crystalline walls using post-template reduction/oxidation
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DOI：
10.1021/ja063662i
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发表时间：
2006-10-04
影响因子：
15
通讯作者：
Bruce, Peter G.
中科院分区：
文献类型：
--
作者：
Jiao, Feng;Jumas, Jean-Claude;Bruce, Peter G.
有序介孔Fe 3 O 4与结晶壁（反尖晶石结构）已首次合成，代表尽我们所知，第一次合成的还原介孔氧化铁。合成是通过还原有序的介孔α-Fe 2 O3（尖晶石结构）的Fe 3 O 4尖晶石，然后通过氧化γ-Fe 2 O3，同时保持有序的介孔结构和结晶壁。这样的固体/固体转变证明了从α-Fe 2 O3的六方密堆积氧化物子阵列（α-Fe 2 O3结构）到Fe 3 O 4尖晶石和γ-Fe 2 O3的立方密堆积子阵列的介观结构到结构相变的稳定性。初步的磁性测量表明，在Fe 3 O 4和γ-Fe 2 O3的自旋冻结在295 K，尽管壁厚（7 nm）小于在相应的纳米粒子（> 8 nm）的冻结的下限。
Ordered mesoporous Fe3O4 with crystalline walls (inverse spinel structure) has been synthesized for the first time, representing to the best of our knowledge, the first synthesis of a reduced mesoporous iron oxide. Synthesis was achieved by reducing ordered mesoporous alpha-Fe2O3 (corundum structure) to Fe3O4 spinel then to gamma-Fe2O3 by oxidation, while preserving the ordered mesostructure and crystalline walls throughout. Such solid/solid transformations demonstrate the stability of the mesostructure to structural phase transitions from the hexagonal close packed oxide subarray of alpha-Fe2O3 (corundum structure) to the cubic close packed subarray of Fe3O4 spinel and gamma-Fe2O3. Preliminary magnetic measurements reveal that the spins in both Fe3O4 and gamma-Fe2O3 are frozen at 295 K, despite the wall thickness (7 nm) being less than the lower limit for such freezing in corresponding nanoparticles (> 8 nm).