MnII Location and Adsorbate Interactions in (M)MnH-SAPO-34 and (W)MnH-SAPO-34 studied by EPR and Electron Spin Echo Modulation Spectroscopies

Abstract

Manganese-doped H-SAPO-34 samples were prepared by an ion-exchanged reaction between H-SAPO-34 and paramagnetic Mn(II) species in methanol media and characterized by ESR and Electron Spin-Echo Modulation(ESEM) studies. In the hydrated (W)MnH-SAPO-34 measured in water, the Mn(II) ion was octahedrally coordinated with four framework oxygens and two water molecules at a displaced site IV of the eight membered ring window in the ellipsoidal cavity, while the Mn(II) ion was octahedrally coordinated to three framework oxygens and three water molecules at a displaced site I’ of the six membered ring window in the ellipsoidal cavity in hydrated(M)MnH-SAPO-34 measured in methanol. The similar result was found in the experiments with methanol adsorbents except ethanol.