Synthesis of a series of oxynitride Ba3-xLaxTa5O14−xN1+x(x = 0–1.5) with a tetragonal tungsten bronze (TTB) structure was examined using moist-NH3and 5% NH3-N2as nitriding atmosphere. The samples with x = 0–1 were successfully obtained as phase pure TTB oxynitride whereas the x = 1.5 samples gave a mixture of TTB oxynitride, Ta3N5, and LaTaO4. Absorption of TTB oxynitrides in visible region was enhanced as increasing the content of nitrogen. TTB oxynitrides exhibited both of H2and O2evolution under visible light in the presence of methanol and silver ions, respectively, as sacrificial reagents. Nitrogen poor surface in the samples synthesized under moist-NH3atmosphere was modified by annealing treatment using 5% NH3, resulting in improvement of photocatalytic activity for H2evolution. Evaluation using monochromatic light revealed that the apparent quantum efficiency of Ba2LaTa5O13N2was higher than that of Ba3Ta5O14N.
- Hydrogen evolution
- Tetragonal tungsten bronze
- Visible-light-driven photocatalyst
ASJC Scopus subject areas
- Environmental Science(all)
- Process Chemistry and Technology