Synthesis and Characterization of Phosphated Mesoporous Titanium Dioxide with High Photocatalytic Activity

TLDR

A surfactant‑templated synthesis incorporating phosphoric acid into TiO₂ yields phosphated mesoporous TiO₂, whose structure and stability were confirmed by XRD, TEM, XPS, UV‑vis, FT‑IR, nitrogen adsorption, and isoelectric point measurements, with stabilization arising from enhanced Ti–OH condensation and suppression of grain growth by an amorphous titanium phosphate matrix. Phosphated mesoporous TiO₂ exhibits a surface area exceeding 300 m² g⁻¹ after 400 °C calcination, shows higher photocatalytic activity than pure TiO₂ in n‑pentane oxidation, and this improvement is attributed to its enlarged surface area, extended band gap, and tetrahedrally coordinated Ti ions.

Abstract

A surfactant-templated approach was used to synthesize phosphated mesoporous titanium dioxide by incorporating phosphorus from phosphoric acid directly into the framework of TiO2. The resulting materials were characterized by XRD, nitrogen adsorption, TEM, XPS analysis, UV−vis spectroscopy, FT-IR spectroscopy, and isoelectric point measurements. The surface area of phosphated mesoporous TiO2 exceeded 300 m2/g after calcination at 400 °C. It was found that the incorporation of phosphorus could stabilize the TiO2 framework and increase the surface area significantly. This stabilization is attributed to two reasons: the more complete condensation of surface Ti−OH in the as-prepared sample and the inhibition of grain growth of the embedded anatase TiO2 by the interspersed amorphous titanium phosphate matrix during thermal treatment. Both pure and phosphated mesoporous TiO2 show significant activities on the oxidation of n-pentane. The higher photocatalytic activity of phosphated mesoporous TiO2 can be explained by the extended band gap energy, large surface area, and the existence of Ti ions in a tetrahedral coordination.