Journal of Physical Chemistry, Vol.98, No.35, 8775-8779, 1994
Structural Defects Cause Different Rates of Phase-Transformation of the Molecular-Sieves Tba-VPI-5 and DPA-VPI-5 into ALPO(4)-8
Chemical analysis, IR, and ESCA reveal that the framework of the aluminophosphate molecular sieve DPA-VPI-5 contains randomly distributed phosphorus defects, while the structure of TBA-VPI-5 is relatively perfect. The microstructural difference is responsible for the different rates of phase transformation of DPA-VPI-5 and TBA-VPI-5 to AlPO4-8. The defects enhance the phase transformation of DPA-VPI-5 to AlPO4-8 in the absence of adsorbed water.