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 0.62 mmol/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 1.1 mmol/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” (Incorporation Model）讨论了这些结果。
： 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 NiO on 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.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2001年第1期43-49,共7页
Chinese Journal of Inorganic Chemistry
基金
国家博士点专项基金资助项目!( No.98028434)。
