催化学报

催化学报 ›› 2007, Vol. 28 ›› Issue (9): 773-778.

• 研究论文 • 上一篇    下一篇

制备方法对负载型纳米ZrO2/Al2O3复合载体性能的影响

李凝1,罗来涛2   

  1. 1 桂林工学院材料与化学工程系, 广西桂林 541004; 2 南昌大学化学系, 江西南昌 330047
  • 收稿日期:2007-09-25 出版日期:2007-09-25 发布日期:2011-09-28

Influence of Preparation Methods on Properties of Nanosized ZrO2/Al2O3 Composite Supports

LI Ning1*, LUO Laitao2   

  1. 1 Department of Material and Chemical Engineering, Guilin Institute of Technology, Guilin 541004, Guangxi, China; 2 Department of Chemistry, Nanchang University, Nanchang 330047, Jiangxi, China
  • Received:2007-09-25 Online:2007-09-25 Published:2011-09-28

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977

被引次数

44

摘要： 采用浸渍-沉淀法制备了负载型纳米ZrO2/Al2O3复合载体. 采用X射线衍射、N2物理吸附、差示扫描量热(DSC)和程序升温脱附等技术考察了浸渍方式和干燥方法对复合载体的表面性能、热稳定性和晶相结构的影响. 结果表明, ZrO2/Al2O3复合载体中没有生成ZrO2-Al2O3复合氧化物或固溶体,纳米ZrO2仅负载在Al2O3的表面. 微波干燥法制备的ZrO2/Al2O3复合载体的比表面积(158.7 m2/g)较大,最可几孔径为19.4 nm, ZrO2的粒度为4.2 nm, 晶相结构为四方相ZrO2. 微波诱导作用使ZrO2/Al2O3复合载体表面产生了新的酸碱中心,微波干燥法制备的ZrO2/Al2O3复合载体具有较强的热稳定性,在873～1073K范围内DSC曲线没有出现吸热峰,而其它干燥方法制备的复合载体在903～1023K范围内出现了较明显的吸热峰,表明复合载体表面的部分四方相ZrO2转变为单斜相ZrO2(m-ZrO2). 对超声波处理过的复合载体进行微波干燥能进一步提高纳米ZrO2与Al2O3之间的相互作用,纳米粒子的粒度(3.4 nm)更小,分布更均匀,但没有改变ZrO2的晶相结构.

关键词: 纳米材料, 氧化锆, 氧化铝, 复合载体, 微波干燥

Abstract: The impregnation-precipitation method was adopted to prepare the nano-sized ZrO2/Al2O3 composite supports. The effects of impregnation and drying methods on the surface properties, thermal stability, and crystal structure of composite supports were characterized byX-raydiffraction, N2 physical adsorption, differential scanning calorimetry (DSC), and temperature-programmed desorption. The results showed that there was no ZrO2-Al2O3 mixture or solid solution formed in the composite, and the nano-ZrO2 was only loaded on the surface of Al2O3. The specific surface area of ZrO2/Al2O3 dried under microwave (158.7 m2/g) was large with the most probable pore size of 19.4 nm, and the particle size of ZrO2 was about 4.2 nm with a tetragonal phase. Microwave induced the formation of new acid-base centers and enhanced the interaction between ZrO2 particles and Al2O3. The ZrO2/Al2O3 composite support prepared by microwave drying had better thermal stability, and there was no absorption peak in the range of 873-1073K in the DSC curves. The ZrO2/Al2O3 composite supports prepared by other methods have an obvious endothermic peak in the range of 903-1023K, indicating that some of the tetragonal ZrO2 crystals on the composite support surface transformed into monoclinic ZrO2. Microwave drying could enhance the interaction between the nano-ZrO2 particles and Al2O3 of the ZrO2/Al2O3 composite support prepared using the ultrasonic method and make the ZrO2 particle size (3.4 nm) smaller, without changing the crystal structure of ZrO2.

Key words: nano-material, zirconia, alumina, composite support, microwave drying