Perovskite-Type LaTiO2N Oxynitrides for Solar Water Splitting: Influence of the Synthesis Conditions
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Date
2012
Publication Type
Conference Paper
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yes
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Abstract
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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published
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Book title
EMRS Symposium T: Materials for solar hydrogen via photo-electrochemical production
Journal / series
Volume
22
Pages / Article No.
61 - 66
Publisher
Elsevier
Event
EMRS Symposium T on Materials for Solar Hydrogen via Photo-Electrochemical Production held at the EMRS Spring Meeting
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Subject
LaTiO2N; Oxynitride; Photocatalysis; Ammonolysis; Perovskite