高等学校化学学报 ›› 2000, Vol. 21 ›› Issue (11): 1733.

• 论文 • 上一篇    下一篇

LaCoO3模型催化剂SO2中毒机理的研究

朱永法, 谭瑞琴, 冯杰, 嵇世山, 曹立礼   

  1. 清华大学化学系, 北京 100084
  • 收稿日期:1999-12-08 出版日期:2000-11-24 发布日期:2000-11-24
  • 通讯作者: 朱永法(1964年出生),男,博士,副教授,从事纳米薄膜材料与环境催化研究.Email:zhuyf@chem.tsinghua.edu.cn
  • 基金资助:

    国家教育部留学回国人员启动基金;清华大学基础研究基金(批准号:97JC33)资助

Studies of SO2 Poisoning Mechanism for Perovskite LaCoO3 Model Catalyst

ZHU Yong-Fa, TAN Rui-Qin, FENG Jie, JI Shi-Shan, CAO Li-Li   

  1. Department of Chemistry, Tsinghua University, Beijing 100084, China
  • Received:1999-12-08 Online:2000-11-24 Published:2000-11-24

摘要: 运用AES,XPS,XRD和TEM等手段研究了LaCoO3模型催化剂SO2中毒过程表面化学状态、晶相结构及表面形貌的变化状况,初步推断了LaCoO3钙钛矿型复合金属氧化物催化剂的SO2中毒机理.在SO2强化中毒过程中,SO2与催化剂的活性组分LaCoO3反应生成硫酸镧和氧化亚钴,而在催化剂膜层内部则生成硫酸镧、亚硫酸镧及氧化亚钴.SO2对活性组分层的侵入及硫与LaCoO3活性组分的反应破坏了催化剂的钙钛矿结构,使得催化剂彻底中毒.当中毒温度较低及中毒时间较短时,硫在膜层中呈峰形分布,其浓度随中毒温度及时间的增加而增加.随中毒温度的升高及中毒时间的增长,由于亚硫酸盐的分解作用,S在活性层中的浓度反而降低,中毒深度则继续增加.

关键词: LaCoO3, SO2中毒机理, 钙钛矿结构, 薄膜

Abstract: In this work, the SO2 poisoning mechanism of model catalyst and powder catalyst of LaCoO3 has been investigated. The changes of the structure and the chemical states of the elements have been characterized using XRD, TEM, AES and XPS. The results showed that the perovskite structure of LaCoO3 was destroyed by the invading of S. Some La2(SO4)3 and CoO species were formed on the surface of the poisoned sample, while La2(SO4)3, La2(SO3)3 and CoO species were the main production in the interior of the LaCoO3 layer, which led to the loss of the catalysis activity. The content of S in the layer increased with the increase of temperature and time. After the sample was poisoned at a relatively high temperature or for a fairly long time, the distribution of S in the LaCoO3 layer became homogeneous with the depth and the concentration being decreased, suggesting that a dynamic equilibrium was achieved between the poisoning reaction and the decomposition of the sulphurous salts.

Key words: LaCoO3, SO2-poisoning mechanism, Perovskite, Film

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