Synergistic effect of different phase on the photocatalytic activity of visible light sensitive silver antimonates

We investigated phase transition of ilmenite-type AgSbO3 to pyrochlore by post-heat treatment and the synergy effect of the mixed phases of AgSbO3 on the photocatalytic activities to enhance the activities. The AgSbO3 with an ilmenite structure was prepared by a cation-exchange method. Phase transition from the ilmenite to pyrochlore occurred by proper control of post-heat treatment. The sample that was obtained by post-heat treatment of ilmenite-type AgSbO3 at 660 °C for 3 h consisted of both of the ilmenite and pyrochlore phases, and the sample at 685 °C for 4 h mainly consisted of the pyrochlore phase. Together with an increase in the ratio of the pyrochlore phase, the optical absorption spectra blue-shifted. The band gaps of single phases of the ilmenite and the pyrochlore were 2.4 and 2.6 eV, respectively. The AgSbO3 sample obtained by post-heat treatment at 660 °C for 3 h showed about eight times and twice higher photocatalytic activity under visible light irradiation than a standard TiO2 photocatalyst (Degussa P25) and single phase of the ilmenite-type sample, respectively, because of the synergy effect.

Ilmenite-type AgSbO3 partially phase-transformed into pyrochlore by post-heat treatment at 660 °C for 3 h and the mixed phase sample was obtained. This mixed phase sample showed about twice and eight times higher photocatalytic activity under visible light irradiation than ilmenite-type AgSbO3 and P25, respectively, because of the synergy effect.Figure optionsDownload high-quality image (125 K)Download as PowerPoint slide