Статья

Perovskite-Type LaTiO2N Oxynitrides for Solar Water Splitting: Influence of the Synthesis Conditions

Alexandra E. MaegliLaboratory for Solid State Chemistry and Catalysis, Empa - Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, SwitzerlandEugenio H. OtalLaboratory for Solid State Chemistry and Catalysis, Empa - Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, SwitzerlandTakashi HisatomiLaboratory of Photonics and Interfaces, EPFL - Swiss Federale Institute of Technology Lausanne, 1015 Lausanne, SwitzerlandSonghak YoonLaboratory for Solid State Chemistry and Catalysis, Empa - Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, SwitzerlandCéline M. LeroyLaboratory of Photonics and Interfaces, EPFL - Swiss Federale Institute of Technology Lausanne, 1015 Lausanne, SwitzerlandNina SchäubleLaboratory for Solid State Chemistry and Catalysis, Empa - Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, SwitzerlandYe LuLaboratory for Solid State Chemistry and Catalysis, Empa - Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, SwitzerlandMichaël GrätzelLaboratory of Photonics and Interfaces, EPFL - Swiss Federale Institute of Technology Lausanne, 1015 Lausanne, SwitzerlandAnke WeidenkaffLaboratory for Solid State Chemistry and Catalysis, Empa - Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland

2012en

ABI

Аннотация

Oxynitrides with the nominal composition LaTiO2N were prepared from a La2Ti2O7 precursor by thermal ammonolysis of the oxide under an NH3 flow for different durations t (4 – 30 h). X-ray diffraction (XRD) indicated that phase-pure LaTiO2N samples were obtained when t ≥ 13 h. The material was further characterised by scanning electron microscopy (SEM), surface area measurements based on the BET method, thermogravimetric analysis (TGA) and UV-visible diffuse reflectance spectroscopy (DRS). The powders displayed an increased crystallite size and a decreased surface area with increasing t. The ratio of N/(N+O) increased with t from 0.22 – 0.27. Correlated to this nitrogen increase, a small variation of the bandgap energy was observed from 2.19 to 2.12 eV with t. All LaTiO2N samples oxidised H2O into O2 in the presence of an electron acceptor (Ag+). The O2 evolution was increased from 12 μmol/h (t = 13 h) to 22 – 24 μmol/h (16 h ≤ t ≤ 30 h). It was found that the nitrogen content and the amount of defects played a key role in the photocatalytic O2 evolution.

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Идентификаторы

DOI: 10.1016/j.egypro.2012.05.218

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