Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/41934
標題: Effect of synthesis pH and H2O molar ratio on the structure and morphology of aluminum phosphate (AlPO-5) molecular sieves
作者: Chen, C.M.
鄭紀民
Jehng, J.M.
關鍵字: AlPO-5 molecular sieve
H2O concentration
pH control
hexagonal pillar
crystal
tridymite structure
crystalline inorganic solids
alpo4-5
conversion
catalysts
期刊/報告no:: Catalysis Letters, Volume 85, Issue 1-2, Page(s) 73-80.
摘要: AlPO-5 molecular sieves were prepared by the hydrothermal reaction of a gel mixture with the following compositions: Al2O3:P2O5:Et3N:H2O = 1:1:1.5:x, where x is between 100 and 750 H2O molar ratio. The structure and morphology of the AlPO-5 molecular sieves depend on the gel mixture's composition, hydrothermal temperature, hydrothermal reaction time, and H. Without H control, the AlPO-5 structure changed from a spherical shape at H2O = 100 to a hexagonal pillar shape at H2O = 450. With pH control in the range of about 2.5-3.5, the hexagonal pillar crystals began to form at H2O = 100 and an island of hexagonal pillars with radiation form appeared at H2O = 300-450 due to the formation of a tridymite type of dense AlPO4 phase. It appears that the formation rate of hexagonal pillar crystals to form a dense AlPO4 phase is favorable under acidic conditions, and an amorphous AlPO-5 structure forms under basic conditions. Thus, the H2O concentration and pH value have a dramatic effect on the AlPO-5 structure.
URI: http://hdl.handle.net/11455/41934
ISSN: 1011-372X
文章連結: http://dx.doi.org/10.1023/a:1022120824681
Appears in Collections:化學工程學系所

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