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Abstract:
The honeycomb-like cordierite is generally employed to act as a catalyst support. However, owing to its low specific surface area, it is required to be coated with porous alumina. In this paper, it was tried to prepare the porous alumina with high surface area on the internal surface of honeycomb-like cordierite through in-situ plus dip-coating method of loading gamma-Al2O3 prior to hydrolysis of the alumina during the process of preparing alumina sol. A desired amount of Al(i-PrO)(3) was added slowly into demineralized water at 83 degreesC with stirring under reflux conditions. After 30 min I the cordierite monolith was added I followed by continuous stirring for 1.5 h. Then the sol stood at 83 degreesC for a sufficiently long time until all of the isopropanol was evaporated by removing reflux condenser. Dilute HNO3 was added to adjust the pH value of the solution to 3.5similar to4.0 for peptization. Then the clear boehmite sol was continuously stirred for 18 h under reflux conditions again. The remained sol in the internal channel of the monolith was removed by air flow. After each dip-coating, the monolith was dried at 120 degreesC for 20 min, and subsequently calcined at 300 degreesC for 20 min. AlOOH coated on the monolith finally converted to gamma-Al2O3 by calcining the coated support at 500 degreesC for 3 h. The in-situ method was improved by combining with conventional dip-coating. The effects of preparation parameters on the loading, crystal composition, and pore structure of the alumina coating were studied, followed by being compared with the corresponding coating prepared through other methods. The alumina coating on the monolith prepared by in-situ method holds good adhesion, but the loading amount per time is lower; the in-situ plus dip-coating method is good for coating, and the resulted alumina coating has good adhesion, illustrating large surface area and, pore volume, and narrow distribution of pore size; the optimum coating parameters are as follows: hydrolysis temperature 83 degreesC, n(H2O)/n (Al(i-PrO)(3)) = 60, pH = 3.5similar to4.0 and calcination temperature 500 degreesC.
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CHINESE JOURNAL OF CATALYSIS
ISSN: 0253-9837
CN: 21-1601/O6
Year: 2003
Issue: 7
Volume: 24
Page: 513-519
0 . 5 4 2
JCR@2003
1 5 . 7 0 0
JCR@2023
ESI Discipline: CHEMISTRY;
JCR Journal Grade:3
Cited Count:
WoS CC Cited Count: 3
SCOPUS Cited Count:
ESI Highly Cited Papers on the List: 0 Unfold All
WanFang Cited Count:
Chinese Cited Count:
30 Days PV: 3
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