Tunable one-pot syntheses of hexagonal-, cubic-, and lamellar-mesostructured vanadium-phosphorus oxides

Hexagonal-, cubic-, and lamellar-mesostructured vanadium-phosphorus oxides were hydrothermally synthesized by using V metal as a reducing agent and a V source. The respective phases were tunably synthesized in the ranges of p H 2.63-2.95, 3.00-3.36, and 3.45-4.45. It is suggested that the formation o f these mesostructured materials depends on the solution species of vanadiu m and phosphorus. The unit cell constants of hexagonal, cubic, and lamellar phases were determined to be a = 5.05 nm, a = 8.54 nm, and c = 3.22 nm, re spectively. IR spectroscopy, XRD, and elemental analyses show that hexagona l- and cubic-mesostructured materials possess an amorphous wall of vanadium -phosphorus oxides and their PN ratios were 0.99 and 0.76, respectively. On the other hand, the lamellar mesostructured material possessed more crysta lline layers of vanadium-phosphorus oxide with a PN ratio of 0.50. The cety ltrimethylammonium templates could be exchanged with K+ or Cs+.