| NiO在γ-Al2O3及 TiO2/γ-Al2O3载体上的表面存在状态 |
| Surface state of NiO supported onγ-Al2O3 and TiO2/γ-Al2O3 supports |
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| 摘要: 本文采用LRS,XRD,UV-DRS,TPR考查了γ-Al2O3上TiO2的分散容量,分散态Ti4+离子的配位环境;NiO在经TiO2改性后的γ-Al2O3载体上的分散容量。结果表明:(1)TiO2在γ-Al2O3表面的分散容量约为0.62mmol/100m2γ-Al2O3,当TiO2含量低于该分散容量时Ti4+在γ-Al2O3载体表面以嵌入形式呈离子态分布;而含量高于分散容量时还有结晶态的TiO2出现。(2)NiO在TiO2/γ-Al2O3载体表面的分散容量约为1.1mmol/100m2γ-Al2O3,比之在γ-Al2O3载体表面的分散容量(1.5mmol/100m2γ-Al2O3)要低,这是由于γ-Al2O3表面上部分空位被Ti4+离子占据。用表面相互作用的“嵌入模型”(IncorporationModel)讨论了这些结果。 |
| 关键词: NiO TiO2 γ-Al2O3 嵌入模型 |
| 基金项目: 国家博士点专项基金资助项目(No.98028434). |
| Abstract: In this paper, Laser Raman spectroscopy (LRS),X-ray diffraction (XRD),Ultraviolet and diffuse reflectance spectroscopy (UV-DRS),and Temperature-programmed reduction (TPR) are used to characterize a serious of TiO2/γ-Al2O3,NiO/γ-Al2O3 and NiO/TiO2/γ-Al2O3 samples.The results showed that (1) the dispersion capacity of titania onγ-Al2O3 is about 0.62mmol/100m2γ-Al2O3. For the TiO2/γ-Al2O3 samples with lower TiO2 loadings (≤ 0.62mmol/100m2γ-Al2O3), only the highly dispersed titania species are formed on the surface probably by the incorporation of the dispersed Ti4+ ions into the surface octahedral vacant sites ofγ-Al2O3, crystalline TiO2 is also formed besides the surface dispersed titania species in the high TiO2 loading samples.(2) The dispersion capacity of NiOon titania-modifiedγ-Al2O3(1.1mmol/100m2γ-Al2O3) is lower than that of NiO, onγ-Al2O3(1.5mmol/100m2γ-Al2O3), which supports the proposal that the dispersion capacity is influenced by the number of the surface vacancies. The coordination environments of the dispersed titania and nickel oxide species onγ-Al2O3 and titania-modifiedγ-Al2O3 are discussed on the basis of the incorporation model proposed previously. |
| Keywords: NiO TiO2 γ-Al2O3 incorporation model |
| 投稿时间：2000-07-06 修订日期：2000-10-09 |
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| 王军,马刚,胡玉海,董林,陈懿.NiO在γ-Al2O3及 TiO2/γ-Al2O3载体上的表面存在状态[J].无机化学学报,2001,17(1):43-49. |
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