Local environment of isolated iron in mesoporous silicate catalyst FeTUD-1

Mesoporous silicate catalyst FeTUD-1 containing only isolated iron was synthesized. Local environment of iron was investigated by X-ray Absorption and Mössbauer spectroscopies. XANES (X-ray Absorption Near Edge Structure) studies show that iron in the as-synthesized and template-free FeTUD-1 is present in the form of Fe3+ ions in coordination geometries posses an inversion center. EXAFS (X-ray Absorption Fine Structure) analyses reveal that iron cations in the as-synthesized sample are coordinated to four oxygens at the distance of 1.87 Å and in the template-free sample to one oxygen at 1.86 Å and five oxygens at 2.0 Å distances. Mössbauer spectroscopy proves the presence of iron in Fe3+ form in template-free sample. Moreover, it determines Fe3+ in two types of distorted octahedral coordinations.