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氧化铝对Pt-SO_4^(2-)/ZrO_2-Al_2O_3固体酸催化剂结构与酸性的影响 被引量:16
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作者 潘晖华 何鸣元 +1 位作者 于中伟 濮仲英 《催化学报》 SCIE CAS CSCD 北大核心 2005年第12期1067-1072,共6页
通过混捏法制备了Pt-SO42-/ZrO2-Al2O3固体酸催化剂,考察了该催化剂在正构烷烃低温异构化反应中的催化稳定性.采用X射线衍射、差热分析、X射线光电子能谱、核磁共振、N2吸附-脱附和微量热等表征技术,对氧化铝的作用机理进行了研究.结果... 通过混捏法制备了Pt-SO42-/ZrO2-Al2O3固体酸催化剂,考察了该催化剂在正构烷烃低温异构化反应中的催化稳定性.采用X射线衍射、差热分析、X射线光电子能谱、核磁共振、N2吸附-脱附和微量热等表征技术,对氧化铝的作用机理进行了研究.结果表明,氧化铝起到结构助催化剂作用,对四方相氧化锆具有稳定作用,并延迟了氧化锆的晶化,抑制了氧化锆的烧结,从而增大了催化剂的比表面积和孔容.XPS结果表明,Zr 3d峰向低结合能方向移动,Al 2p峰向高结合能方向移动,说明Al3+的电子向Zr4+偏移.微量热结果表明氧化铝的引入提高了催化剂的酸量和酸强度.27Al固体核磁共振结果表明,Pt-SO42-/ZrO2-Al2O3中的六配位铝的结构发生了变化.氧化铝的引入还可能有助于氧化锆晶格缺陷的形成,焙烧过程中Al3+迁移进入氧化锆晶格并同晶取代Zr4+形成氧缺陷位,这些氧缺陷位在S=O键诱导下显示强酸性. 展开更多
关键词 混捏法 氧化锆 氧化铝 固体 正戊烷 异构化 酸位模型
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Acid Dissociation Constants of Functional Groups in Humic Substances:I.Affinity Spectrum Model Analysis of Potentiometric Data of Fulvic and Humic Acids Solutions from Weathered Coal and Dark Loessial Soil 被引量:1
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作者 DUJIN-ZHOU LUCHANG-QING 《Pedosphere》 SCIE CAS CSCD 1994年第3期201-208,共8页
Potentiometric experiments were carried out on the proton binding equilibria of FA extracted from a weathered coal and HA and Fa extracted from a dark loessial soil.The affinity spectrum model was employed to treat th... Potentiometric experiments were carried out on the proton binding equilibria of FA extracted from a weathered coal and HA and Fa extracted from a dark loessial soil.The affinity spectrum model was employed to treat the experimental data.The affinity spectrum model technique could“magnify” the heterogeneity of the proton binding equilibria.so it was useful for comparing and studying the characteristics of humic substances with similar properties.According to the affinity spectra,we also found that the direction of the titration could affect the properties of the equilibria of FA from the weathered coal,and the acidic functional groups contained in FA from the weathered coal were larger in quantity than those contained in HA and FA from the dark loessial soil. 展开更多
关键词 affinity spectrum HETEROGENEITY humic substances potentiometric titration
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