期刊
MICROPOROUS AND MESOPOROUS MATERIALS
卷 147, 期 1, 页码 167-177出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.micromeso.2011.06.012
关键词
Mesoporous; Aluminas; Morphology
类别
资金
- National Science Foundation of China [20890124]
- National High Technology Research and Development Program of China [2009AA064201]
- Shanghai Leading Academic Discipline Project [B409]
Aluminum hydroxides were synthesized through the acidification of sodium aluminate solution using single organic diester or diacid as pH adjustor and aluminum chelating agent. The obtained alumina hydrates are investigated by XRD, SEM, IR and TG. Bayerite firstly formed at room temperature, and its morphology greatly varied with the pH adjustors used, which probably attributes to different kinetics of the acidification. The bayerite can evolve to gibbsite and boehmite after the hydrothermal treatment at 100 C and 145 C, respectively, where these alumina hydrates show diverse morphologies. After the calcination, these alumina hydrates of bayerite, gibbsite and boehmite could pseudomorphically transform to the corresponding eta-, chi- and gamma-aluminas, respectively, exhibiting different structural and textural properties. Interestingly, the transition aluminas derived from the aluminum tri-hydroxides, bayerite and gibbsite, both display locally organized mesopores, while no such meso-structure can be observed in gamma-alumina obtained from the aluminum mono-hydroxide, boehmite. The changes of bayerite during calcination are investigated detailed. The dehydration of non-porous bayerite accompanied with the formation of meso-structured transition aluminas, where the meso-structure becomes more and more clearly defined and pore size expands with the calcination temperature increasing. (C) 2011 Elsevier Inc. All rights reserved.
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