Investigations on iron substitution in VPI-5 and its redox behavior

An extra-large pore iron-substituted aluminophosphate molecular sieve FeVPI-5 was synthesized. Elemental analysis indicated isomorphous substitution of aluminum by iron. X-ray absorption spectroscopy (XANES and EXAFS analyses) confirmed the incorporation of Fe(III) into the framework of VPI-5. The acidity tests of FeVPI-5, performed by IR spectroscopy using CO adsorption at low temperature on the oxidized and on the reduced material, gave evidence on redox behavior of framework iron in FeVPI-5.