Dynamics of water molecules in micropores of AlPO₄-5 and SAPO-5 studied by ¹H NMR

Dynamics of water molecules in one-dimensional micropores AlPO₄-5 and SAPO-5 frameworks was studied by measuring ¹H NMR spectra, second moment M₂ of line-width and spin-lattice relaxation time T₁. Although the presence of two kinds of water molecules free and bound on the capillary wall were reported in AlPO₄-5, our NMR T₁ results imply the absence of two kinds of H₂O motions, but the motional rate distributes from slow to fast jumps in both AlPO₄-5 and SAPO-5.