Synthesis and photophysical properties of barium indium oxides

Abstract

Barium indium oxides (BaIn2O4, Ba4In6O13, Ba2In2O5, Ba3In2O6, and Ba5In2O8) were synthesized by the citric process and characterized by powder x-ray diffraction. The optical absorption properties of these compounds were investigated by UV–visible diffuse reflectance spectroscopy. It was found that with the increase of the mole ratio of In2O3 in the formula the optical absorption edges of these oxides shift to the longer wavelength side monotonically. The photocatalytic H2 and O2 evolutions under visible light irradiation (λ > 420 nm) from aqueous CH3OH/H2O and AgNO3/H2O solutions were performed. Among these oxides, BaIn2O4 was the most stable compound, and other compounds were not stable chemically in the case of water and visible light irradiation.