Perovskite-type oxides synthesized by reactive grinding Part I. Preparation and characterization
Perovskite-type oxides synthesized by reactive grinding Part I. Preparation and characterization
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DOI：
10.1016/s0926-860x(00)00779-1
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发表时间：
2001-02-28
影响因子：
5.5
通讯作者：
Muzychuk, R
中科院分区：
文献类型：
--
作者：
Kaliaguine, S;Van Neste, A;Muzychuk, R
以LaCoO_3和LaCoFeO_3为原料，采用机械合成法，采用反应研磨法制备了钙钛矿型材料LaCoO_3和LaCoFeO_3。当使用研磨添加剂时，通过该方法产生的钙钛矿具有前所未有的高比表面积（>100 m2/g），并且它们的表面化学性质特别令人感兴趣。钙钛矿表面显示出大浓度的表面OH（由于低研磨温度），其在煅烧时导致材料晶格的重新形成。在煅烧过程中氧的存在引发了竞争过程，其使具有过量电子电荷的位点稳定，在氧解吸（Co2+）时产生还原的Co位点。XPS分析表明，这些减少的Co2+离子浓度与煅烧温度的增加。在高煅烧温度（>673 K）下，TPD研究显示源自本体的β-氧的释放。(C)2001 Elsevier Science B. V.保留所有权利。
Perovskite-type materials LaCoO3 and LaCoFeO3 were prepared from their component oxides using mechano-synthesis, by a new method of preparation designated as reactive grinding. When grinding additives are used, the perovskites generated via this process are of unprecedently high specific surface area (>100 m(2)/g) and their surface chemical properties are of particular interest. The perovskite surface shows a large concentration of surface OHs (due to the low grinding temperature) which upon calcination leads to reformation of the materials lattice. The presence of oxygen during calcination initiates a competitive process, which stabilizes sites with an excess of electronic charge, yielding reduced Co sites upon oxygen desorption (Co2+). XPS analysis illustrates an increase in these reduced Co2+ ion concentration with calcination temperature. At high calcination temperature (>673 K), TPD studies show the release of beta -oxygen originating from the bulk. (C) 2001 Elsevier Science B.V. All rights reserved.