Lamellar α‑Titanium Phosphate Modified with Magnesium Sulfate: Effects on Structural, Thermal, Morphological, and...

Broadly speaking, hierarchically structured materials are those in which their structural regularity in different length scales can permit the enhancement of their multifunctional properties. α-Titanium phosphate (α-TiP) is considered like a material with a hierarchical arrangement. In this context, this study intended to investigate the effect of the incorporation of magnesium sulfate (MgSO₄) on α-TiP physicochemical properties. α-TiP was synthesized using titanium isopropoxide and phosphoric acid. Either synthesized or intercalated with ethylamine aqueous solution, MgSO₄ was added into ETiP via solvent-based and dry handling mixing routes. Structural, thermal, morphological, and electrochemical properties were analyzed. X-ray diffraction revealed that the presence of an ethylamine aqueous solution influenced the interlamellar layer of phosphate. The route of MgSO₄ intercalation induced variation on its amount inside the phosphate galleries as seen by SEM/EDS. A possible interaction between magnesium salt and ethylamine through hydrogen bond formation was hypothesized. Raman spectroscopy indicated spectral changes depending on the route of magnesium salt incorporation. Spin-lattice (T₁H) and spin-spin (T₂H) time relaxations revealed that the role of ethylamine aqueous solution as an intercalator was crucial on the phosphate molecular mobility after addition of MgSO₄. Electrochemical impedance showed that the ETiP/EMgSO₄ sample showed the best Nyquist and Bode diagrams. Plot of current versus voltage indicated that solvent-based sample ETiP/EMgSO₄ showed electrical conductivity while that named dry handling mixing αTiP/MgSO₄(MF) is an insulator. The ETiP/EMgSO₄ sample exhibited lower impedance around 2 to 3 orders of magnitude lower than precursors. Ethylamine aqueous solution played a key role in modulating phosphate properties and MgSO₄ mobility within the phosphate matrix.