改进共沉淀法以提高三效催化剂中铈锆复合氧化物的热稳定性

doi:10.15541/jim20160288

摘要/Abstract

摘要：

采用共沉淀法制备了铈锆材料(铈锆比为3/2)。通过改进反应器装置(图1), 延长了初始晶粒生长的时间, 提高了铈锆材料的热稳定性。采用X射线衍射(XRD)、氮气吸脱附和透射电镜(TEM)对制备的材料进行了表征。结果表明, 延长初始晶粒生长的时间可以得到较大尺寸的晶粒, 这有利于提高材料的织构和结构性能, 从而提高热稳定性。本研究将该材料应用于单Pd三效催化剂, 表现出了优异的活性和热稳定性, 具有良好的应用前景。

关键词: 铈锆材料, 初始晶粒, 共沉淀法, 热稳定性

Abstract:

A series of ceria-zirconia mixed oxides (CZ-x; x=0, 20, 40 and 80) with Ce/Zr molar ratio of 3/2 were synthesized by co-precipitation method. In order to improve the thermal stability of ceria-zirconia mixed oxides, we extended the time for the primary grain to grow up by a modified synthesis reactor. The resulting samples were characterized by X-ray diffraction (XRD), N₂ adsorption-desorption, and transmission electron microscopy (TEM). The results revealed that bigger grain could be obtained by extending time for the primary grain to grow up, which was propitious to enhance the textural properties and structural properties of the materials. Thus, the thermal stability of the materials was improved. In this study, the materials were applied in the field of Pd-only three way catalysts (TWCs). The catalysts exhibited excellent catalytic performance and thermostability, showing better prospect in application.

Key words: ceria-zirconia composites, primary grain, co-precipitation, thermostability

中图分类号:

TQ174

伍青峰, 崔亚娟, 张海龙, 周怡, 兰丽, 王健礼, 陈耀强. 改进共沉淀法以提高三效催化剂中铈锆复合氧化物的热稳定性[J]. 无机材料学报, 2017, 32(3): 331-336.

WU Qing-Feng, CUI Ya-Juan, ZHANG Hai-Long, ZHOU Yi, LAN Li, WANG Jian-Li, CHEN Yao-Qiang. Preparation of Ceria-zirconia Mixed Oxides with Improved Thermal Stability for Three-way Catalysts by a Modified Co-precipitation Method[J]. Journal of Inorganic Materials, 2017, 32(3): 331-336.

图/表 12

参考文献 19

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Samples	Phase composition	Lattice parameter/nm	Crystallite size/nm
CZ-0-d	Cubic	0.5421	3.7
CZ-20-d	Cubic	0.5422	3.8
CZ-40-d	Cubic	0.5380	4.0
CZ-80-d	Cubic	0.5380	4.3
CZ-0-f	Cubic	0.5274	4.8
CZ-20-f	Cubic	0.5284	4.8
CZ-40-f	Cubic	0.5271	5.0
CZ-80-f	Cubic	0.5291	4.9
CZ-0-a	Cubic + tetragonal	0.5258^a	21.2
CZ-20-a	Cubic + tetragonal	0.5261^a	19.3
CZ-40-a	Cubic + tetragonal	0.5286^a	17.2
CZ-80-a	Cubic	0.5292	14.5

Samples	Phase composition	Lattice parameter/nm	Crystallite size/nm
CZ-0-d	Cubic	0.5421	3.7
CZ-20-d	Cubic	0.5422	3.8
CZ-40-d	Cubic	0.5380	4.0
CZ-80-d	Cubic	0.5380	4.3
CZ-0-f	Cubic	0.5274	4.8
CZ-20-f	Cubic	0.5284	4.8
CZ-40-f	Cubic	0.5271	5.0
CZ-80-f	Cubic	0.5291	4.9
CZ-0-a	Cubic + tetragonal	0.5258^a	21.2
CZ-20-a	Cubic + tetragonal	0.5261^a	19.3
CZ-40-a	Cubic + tetragonal	0.5286^a	17.2
CZ-80-a	Cubic	0.5292	14.5

Samples	Specific surface/(m²·g^-1)	Pore volume/(cm³·g^-1)	Average pore radius/nm
CZ-0-f	118	0.25	4.2
CZ-20-f	137	0.27	3.9
CZ-40-f	120	0.27	4.5
CZ-80-f	129	0.30	4.6
CZ-0-a	16	0.08	10.7
CZ-20-a	15	0.07	9.3
CZ-40-a	22	0.11	10.2
CZ-80-a	29	0.13	9.0

Samples	Specific surface/(m²·g^-1)	Pore volume/(cm³·g^-1)	Average pore radius/nm
CZ-0-f	118	0.25	4.2
CZ-20-f	137	0.27	3.9
CZ-40-f	120	0.27	4.5
CZ-80-f	129	0.30	4.6
CZ-0-a	16	0.08	10.7
CZ-20-a	15	0.07	9.3
CZ-40-a	22	0.11	10.2
CZ-80-a	29	0.13	9.0

Samples	Below 3 nm	Between 3 nm and 6 nm	Above 6 nm
CZ-0-f	37.6%	32.7%	29.7%
CZ-20-f	39.0%	31.1%	29.9%
CZ-40-f	30.1%	40.6%	29.3%
CZ-80-f	22.8%	47.8%	29.4%