A Simple Route for the Synthesis of Mesostructured Lamellar and Hexagonal Phosphorus-Free Titania (TiO₂)

Abstract

A new synthetic approach to generate mesostructured phosphorus-free titania is reported. Mesostructured hexagonal and lamellar titania were prepared by using the cationic surfactant C16TMA+ and soluble peroxytitanates in the presence of Na+ and TMA+, respectively. Moreover, upon hydrothermal postsynthesis, the lamellar mesophase can be converted to the hexagonal mesophase in the presence of Na+ in the liquid phase. In contrast, the lamellar structure is stable and improves under similar conditions when Na+ is replaced by TMA+.

Recent progress in mesoporous titania materials: adjusting morphology for innovative applications

“…Therefore, the phosphorous-free synthesis method is very important for mesoporous pure titania materials. The preparation of mesostructured phosphorus-free titanium oxide in the presence of Na + and TMA + (tetramethyl ammonium hydroxide) using a cationic surfactant (CTABr) as a structure-directing agent and soluble peroxytitanate as a precursor, respectively, was also reported [15]. Yang et al described the synthesis of thermally stable and large-pore mesoporous metal oxides using block copolymers as structure-directing agents [16].…”

Ordered Meso‐ and Macroporous Binary and Mixed Metal Oxides

“…Tammann temperatures of some common transition-metal oxides. [5,34] [56] hexagonal (a = 39) Vanadium oxide [a] V 2 O 5 , DTABr, H 2 O lamellar (c = 21.6) [57] Vanadium oxide [a] oxovanadium triisopropoxide, dodecylamine, ethlamellar (c = 23-28) [58] anol/H 2 O hexagonal (a = 34.6) Vanadium oxide [a] VCl 4 , triblock copolymers, ethanol mesostructured (lack of long-range order) [59] (maximum d-spacing 111) Vanadium oxide [c] VOSO 4 , P123, ethanol/H 2 O wormhole like [60] ( [57] Molybdenum oxide [a] MoCl 5 , triblock copolymers, ethanol mesostructured (lack of long-range order) [59] (maximum d-spacing 100) Niobium oxide [b] niobium ethoxide, sodium dodecyl sulfate, solamellar (c = 25) hexagonal (a = 32-52), cu- [61,62] dium dodecyl phosphonate, primary alkylamines bic (d-spacing 48) Niobium oxide [b] NbCl 5 , tribolck copolymers, ethanol hexagonal [59,63] (a = 32-52) Titanium oxide [b] TiCl 4 , triblock copolymers, ethanol hexagonal (a = 117) [59,63] cubic (a = 107) Titanium oxide [c] peroxytitanates, CTACl, H 2 O lamellar (c = 31) [69] hexagonal (d-spacing 41) Titanium oxide [a] titanium isopropoxide, CTABr, ethylene glycol, mesostructured (lack of long-range order) [70] NaOH, (channel spacings 50) Zirconium oxide [b] zirconium n-propoxide, H 2 O, carboxylates, alkyl lamellar, [80] sulfonates, dodecyl sulfate, primary alkylamines hexagonal, mesostructured (lack of long-range order) (maximum d-spacings = 16-40) Zirconium oxide [b] ZrCl 4 , triblock copolymers, ethanol hexagonal [59,63] (a = 122) Zirconium oxide [a] Zr(OC 2 H 5 ) 4 , CTABr, ethylene glycol, NaOH mesostructured [70] (la...…”

“…[68] Mesoporous TiO 2 has been obtained using different synthetic approaches. [59,63,69,70] Stucky et al [59,63] have employed hydrogen bonding to direct the synthesis and obtained large-pore (ca. 65 Å) hexagonal and cubic meso-porous TiO 2 with a specific surface area of 200 m 2 /g.…”

“…Interestingly, the walls of the TiO 2 mesostructure were built of nanocrystalline anatase, which is promising for potential applications in photocatalysis, since anatase is the most photocatalytically active crystalline phase of TiO 2 . [65] In a different approach, charge matching between cationic surfactants and anionic peroxytitanates was used to produce mesoporous TiO 2 [69] with a surface area of 310 m 2 /g and a pore size of about 36 Å. The final mesostructure, however, was found to lack long-range order, thus suggesting the formation of a wormhole pore network.…”

Design and applications of a home-built in situ FT-Raman spectroscopic cell

“…Since the first successful combination of sol-gel chemistry and self-assembly in the synthesis of ordered mesoporous silica [20], a variety of different framework compositions have been synthesized [21][22][23][24], such as vanadia, titania, zirconia,. .…”