Template synthesized nano-crystalline natrotantite: Preparation and photocatalytic activity for water decomposition

A new method for preparation of natrotantite (Na2Ta4O11) by hydrothermal method using cetyl trimethyl ammonium bromide (CTAB) template is reported. The nano, mesoporous and crystalline natrotantite resulted during different methods adopted for surfactant removal. Nano-crystalline natrotantite was observed during template removal using ethanol. The meso and crystalline samples resulted during the high temperature calcination at 773 and 1373 K, respectively. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), UV-vis diffraction reflected spectra (DRS), N-2-adsorption isotherm and surface area measurements. Nano, mesoporosity of the sample was confirmed by TEM, N2-adsorption isotherm studies. The band gaps of the nano, mesoporous and crystalline natrotantite were estimated to be 4.1, 4.3 and 3.9 eV with surface areas of 42.4, 133.6 and 6.21 m(2) g(-1), respectively. Furthermore, nano-crystalline Na2Ta4O11 is found to be highly efficient photocatalyst for water decomposition. (C) 2008 Elsevier B.V. All rights reserved.