Characterization of alumina gel catalysts by emanation thermal analysis (ETA)

Hiroshi Hirashima, Hiroaki Imai, Vladimir Balek

研究成果: Conference article査読

2 被引用数 (Scopus)

抄録

Alumina gels made from the metal alkoxide is known to have high catalyst activity for the selective reduction of NOx by hydrocarbons. It is also reported that the fine structure of the gels effects the activity. In this study, the effect of the preparation method on the fine structure and catalyst activity of the gels was investigated. Monolithic gels were obtained by hydrolysis of Al(sec-C4H9O)3. The wet gels were dried at 90°C (xerogels), supercritically dried (aerogels), or dried after immersion in an ethanol solution of methyltrimethoxysilane (modified xerogels). The changes in the microstructure during heating were discussed using the results of TG-DTA, ETA and N2 adsorption. The ETA curves show the 220Rn-release rate, E, of the samples, previously labelled with 228Th and 224Ra, during heating. The decrease in E of the xerogel at temperatures higher than 400°C indicates a gradual decrease in the surface area and porosity. A remarkable decrease in the BET surface area of the xerogel was found after heat-treating at 500°C. On the other hand, constant E of the aerogels and modified xerogels above 450°C suggests high thermal stability. The pore radii, estimated by BJH method, and the catalyst activities at 500°C of the aerogels and the modified xerogels were higher than those of the xerogels. The temperature range in which the alumina gels are applicable as catalysts was determined.

本文言語English
ページ(範囲)399-402
ページ数4
ジャーナルJournal of Sol-Gel Science and Technology
19
1-3
DOI
出版ステータスPublished - 2000 12月
イベント10th International Workshop pn Glass and Ceramics, Hybrids and Nanocomposites from Gels - Yokohama, Jpn
継続期間: 1999 9月 201999 9月 24

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • セラミックおよび複合材料
  • 化学 (全般)
  • 生体材料
  • 凝縮系物理学
  • 材料化学

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