A new and facile route to prepare mesoporous tantalum phosphate with high surface area using tantalum tartrate precursor

Mesoporous amorphous tantalum phosphate (TP) has been synthesized through a simple precipitation technique using aqueous solution of tantalum tartrate complex and diammonium hydrogen phosphate as precursors of tantalum and phosphorous respectively and a cationic surfactant tetradecyltrimethylammonium bromide (TTBr) as a structure directing agent. The optimized mesoporous amorphous TP shows high surface area (359 m2/g), narrow pore size distribution (2.3–10 nm) and considerable pore volume (0.410 ml/g) after calcinations at 550 °C. Thermal effect on the as-synthesized TP has been investigated through thermogravimetric and differential thermal analysis and the structural characterizations of mesoporous TP calcined at 550 °C for 4 h have been carried out by low angle X-ray diffraction, Fourier transformed infrared spectroscopy, 31P magic angle spinning nuclear magnetic resonance spectroscopy, UV–visible diffuse reflectance spectroscopy. High resolution transmission electron microscopy study shows the presence of wormlike mesopores and the selected area electron diffraction pattern depicts the amorphous nature of mesoporous TP. The interaction of NH3 with TP has been investigated by means of temperature-programmed desorption of ammonia which indicates the existence of acidic sites of moderate strength on the surface of mesoporous TP.