Synthesis and application of mesoporous AIPO₄-5 and SAPO-5 by atrane precursor via microwave heating

Abstract

Alumatrane and silatrane were successfully used as aluminum and silica sources, respectively, for the preparation of mesoporous AIPO 4 - 5 and SAPO -5 zeotype with AFI-type structure under microwave heating using triethylam ine (TEA) as structure directing agent. The influences of chemical composition , aging time, and microwave temperature and time were investigated. The results showed that a long hexagonal rod-like structure was formed in the case of mesoporous AIPO4 - 5 zeotype. Amounts of the structure-directing agent and water; reaction temperature and time affected on crystal morphology and crystallinity. The lower microwave temperature can be compensated by the longer crystallization time. The presence of Si in the synthesis mixture forming SAPO -5 zeotype with AFI-type structure disturbed the crystals’ growth in the c-direction, as a result, becoming a short plate-like hexagon. TEM results showed that the samples contained a classical single crystal and 10 -100nm mesoporous matrix nanostructure having the AFI structure. The synthesis of silicoaluminophosp hate (SAPO) without adding the TEA structure-directing agent resulted in flower-like SAPO consisting of six petals due to the generation of trialkanoamines molecules during hydrolysis of alumatrane and silatrane that could be other structure-directing agents in the system . Moreover, the mesoporous AIPO4 -5, SAPO -5, and flower-like SAPO were also used as catalyst support for Pt catalyst over the preferential oxidation (PROX ) o f CO reaction, show in g a 100% CO conversion , indication that they are useful to completely remove CO contaminated in the H 2 rich feed gas as a fuel in proton exchange mem brane fuel cells (PEMFC) to protect degradation of the platinum electrode.