Synthesis and characterization of Ti_1−2x(FeNb)_xO₂ solid solutions for visible-light-active photocatalyst

Abstract

Ti_1−2x(FeNb)_xO₂ solid solutions were prepared as visible-light-active photocatalysts using a conventional solid-state reaction method. Ti_1−2x(FeNb)_xO₂ solid solutions were obtained below x = 0.25 without any secondary phase. They exhibited light absorption in the visible region. The strong absorption corresponding to the bandgap shifted to the lower energies with increasing x. Because the valence band maxima of the samples remained unchanged, the conduction band minima shifted to lower energies. The photocatalytic activity was evaluated based on the degradation of methylene blue under UV–visible light irradiation. The photocatalytic activity of Ti_1−2x(FeNb)_xO₂ solid solutions tends to improve with increasing x. Clear visible light photocatalytic activity corresponding to the band gap was also observed. Thus, these materials are promising candidates for environmental applications.