| 不同制备方法和反应条件对Fe2O3形貌和晶型转变的影响 |
| Influence of Different Preparation Methods and Reaction Conditions on Morphology and Crystallization Transformation of Fe2O3 |
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| 摘要: 研究了吸附相反应技术、浸渍法以及沉淀法制备Fe2O3的过程中，反应环境的变化对粒子形貌和晶型转变过程的影响。当吸附层是主要反应场所时，生成的粒子与SiO2表面以较强的化学键键合，焙烧过程中Fe2O3的晶型变化和粒子团聚被有效地抑制，焙烧后Fe2O3粒子维持稳定的γ-Fe2O3晶型和高分散的小粒子。而在乙醇体相中反应生成的粒子，仅通过物理作用与SiO2表面结合，不能有效抑制其向α-Fe2O3晶型的转变和粒子的团聚。吸附相反应制备过程中，当水量持续增加或者体系温度升高，反应环境逐渐从吸附层向乙醇体相中转变，SiO2对Fe2O3晶型转变的抑制作用减弱，从而导致样品中逐渐出现α-Fe2O3晶型。 |
| 关键词: 吸附相反应技术 反应历程 Fe2O3纳米粒子 γ-Fe2O3 α-Fe2O3 晶型转变 |
| 基金项目: |
| Abstract: The influence of reaction process on morphology and crystallization of Fe2O3 was studied for preparation of Fe2O3 by Adsorption Phase Synthesis(APS), Impregnation Method(IM) and Precipitation Synthesis(PS). When the adsorption layer is the major reaction site, the generated Fe2O3 particles combine with the silica surface via strong chemical bonding, which inhibits significantly the phase transformation and aggregation of Fe2O3 during calcination process. Therefore Fe2O3 particles with γ-Fe2O3 phase and small size are kept stable after sintering. While the particles formation happens in the bulk alcohol, the physical combination between particles and the surface of SiO2 is so weak that both aggregation of particles and the crystal transformation from γ-Fe2O3 to α-Fe2O3 could not be effectively prevented. In preparation of Fe2O3 by APS, reaction site transfers gradually from the adsorption layer to the bulk alcohol with increase in water concentration or temperature in the system, which weakens the control effect of silica on crystal transformation of Fe2O3, resulting in α-Fe2O3 phase gradually in the samples. |
| Keywords: adsorption phase synthesis reaction mechanism Fe2O3 nanoparticles γ-Fe2O3 α-Fe2O3 crystallization transformation |
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| 王 挺,蒋 新,黄焕聪.不同制备方法和反应条件对Fe2O3形貌和晶型转变的影响[J].无机化学学报,2010,26(7):1153-1158. |
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