文献类型：期刊文献

中文题名：制备方法对γ-Al_2O_3载体水热稳定性的影响

英文题名：Influence of Preparation Methods and Additives on Hydrothermal Stability of γ Al 2O 3

作者：赫崇衡[1];郭杨龙[1];汪仁[1]

机构：[1]华东理工大学工业催化研究所

年份：1998

卷号：27

期号：1

起止页码：27

中文期刊名：石油化工

外文期刊名：Petrochemical Technology

收录：CSTPCD;;EI(收录号：1999414770015);Scopus;北大核心:【北大核心1996】；CSCD:【CSCD2011_2012】；

语种：中文

中文关键词：γ-Al2O3;烧结;水热稳定性;制备;催化剂载体

外文关键词：gamma alumina,sintering,hydrothermal stability,preparation,rare earth

摘要：用溶胶－凝胶法、浸渍法和共沉淀法制备了γ－Ａｌ２Ｏ３样品，并通过添加Ｌａ２Ｏ３、ＣｅＯ２等稳定剂对γ－Ａｌ２Ｏ３进行表面修饰。考察了在１２７３Ｋ的空气和水蒸汽存在下γ－Ａｌ２Ｏ３的烧结行为，经ＢＥＴ比表面、ＤＴＡ、ＸＲＤ衍射及其宽化法表征了各样品在不同烧结时间晶相、晶粒大小、比表面和孔径分布的变化。发现添加Ｌａ２Ｏ３对提高γ－Ａｌ２Ｏ３向α－Ａｌ２Ｏ３的相变温度和阻滞其颈部烧结的作用比ＣｅＯ２强得多。此外，采用ｓｏｌ－ｇｅｌ法制备的样品对提高γ－Ａｌ２Ｏ３的微孔稳定性及抗烧结性也有明显的促进作用。通过对１２７３Ｋ下水热烧结动力学的研究发现，经ｓｏｌ－ｇｅｌ法和浸渍法制备的含质量分数为５％Ｌａ２Ｏ３的载体，其烧结机理为体积扩散过程，而共沉淀法制备的载体之烧结为表面扩散机理。
Samples of gamma aluminas were prepared by sol gel,impregnation and coprecipitation methods and the influence of lanthana and ceria on the hydrothermal stability of alumina was investigated by wide angle X ray diffraction and BET surface area measurements It was found that samples prepared by sol gel methods possessed larger surface area and higher durability after sintering in wet air (14% water) at 1273K as compared with those prepared by other methods Upon addition of rare earth to alumina using the sol gel method,the grain growth of transition alumina and the formation of alpha alumina were further retarded The modification by lanthanum was more effective than that by cerium for improving the hydrothermal resistance of gamma alumina The studies of sintering kinetics for the reduction in specific surface area show that the sintering of gamma alumina proceeds via volume diffusion mechanism for the sol gel and impregnation products and via surface diffusion for the coprecipitation product