Accessing alkali-free NASICON-type compounds through mixed oxoanion sol-gel chemistry: Hydrogen titanium phosphate sulfate, H1-xTi2(PO4)3-x(SO4)x (x=0.5-1)

Daniel Mieritz, Stephen K. Davidowski, Dong Kyun Seo

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2 Citations (Scopus)


We report a direct sol-gel synthesis and characterization of new proton-containing, rhombohedral NASICION-type titanium compounds with mixed phosphate and sulfate oxoanions. The synthetic conditions were established by utilizing peroxide ion as a decomposable and stabilizing ligand for titanyl ions in the presence of phosphates in a strong acidic medium. Thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), induction-coupled plasma optical emission spectroscopic (ICP-OES) elemental analysis, and Raman and 1H magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopic studies have determined the presence of sulfate and proton ions in the structure, for which the compositional range has been found to be H1-x Ti2(PO4)3-x (SO4) x (x=0.5-1). The particulate products exhibit a nanocrystalline nature observed through characterization with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The N2 sorption isotherm measurements and subsequent Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) analyses confirmed the presence of the textural meso- and macropores in the materials. Future studies would determine the potential of the new compounds in various applications as battery materials, proton conductors and solid acid catalysts.

Original languageEnglish
JournalJournal of Solid State Chemistry
Publication statusAccepted/In press - Dec 1 2015



  • Battery material
  • Mixed oxoanion
  • NASICON-type oxides
  • Sol-gel synthesis

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Physical and Theoretical Chemistry
  • Ceramics and Composites
  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry

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