Titanium terephthalate (TT-1) hybrid materials with high specific surface area

Abstract

A porous inorganic–organic titanium terephthalate (TT-1) based hybrid material is prepared using a solvothermal synthesis without templates. The nitrogen physisorption measurements show a combination of type IV and type I isotherms with a broad pore size distribution and a high specific BET surface area of S_g = 534 m² g⁻¹. The material has predominately mesopores (BJH pore volume = 0.54 cm³ g⁻¹), with a small amount of micropores (specific micropore volume V_g = 0.11 cm³ g⁻¹). The IR and solid state ¹³C MAS NMR spectra indicate coordination of the terephthalate ligand to Ti⁴⁺ ions and the ligand is a building block of the TT-1 hybrid material. The energy difference of 189 and 160 cm⁻¹ between ν_asym(COO⁻) and ν_sym(COO⁻) indicates monodentate and bridging coordination of the terephthalate group, respectively. According to X-ray powder diffraction patterns TT-1 is amorphous. Upon heat treatment at 400 °C crystallisation of anatase and a significant loss of the specific surface area is detected.