N-doped NaTaO3: novel visible-light-driven photocatalysts synthesised by a sol-gel method

N-doped NaTaO3 catalysts were synthesized via a sol-gel method followed by a subsequent calcination process under NH3 atmosphere. The as prepared samples were characterized by XPS, XRD, UV-Vis DRS, and BET analyses. All XRD peaks of the sample calcined at 900 A degrees C matched with pure perovskite NaTaO3 while peaks of TaON and Na2Ta4O11 were found for that calcined at 1,000 A degrees C. The DRS of samples shown cutoff edge has red shifted, from 315 nm of pure to 391 nm of N-doped NaTaO3. N-doping helps to narrow the band gap, and the prepared sample was visible light sensitive. The XPS spectrum of Ta4p3&N1s shown two new peaks at 398.3 and 401.4 eV appear in the N-doped sample corresponding to Ta-N bonds and adsorption nitride, respectively. Photocatalytic activity of the catalysts was evaluated using Rhodamine B dye. The result demonstrated that the sample calcined under NH3 had a higher photocatalytic activity than that of P25 under visible light. The NaTaO3/TaON heterojunction played an important role on promoting photoactivity.