Synthesis and Characterization of Yb−Ag@TiO₂ Hollow Spheres for Enhancing Visible‐Light Photocatalytic Activity

Abstract

Using melamine‐formaldehyde microspheres as templates and n‐butyl titanate, silver nitrate and ytterbium nitrate hexahydrate as raw materials, the TiO2 hollow spheres (TiO2HS), which were doped with Yb and loaded with Ag, were successfully prepared by sol‐gel template method and high‐temperature calcinations and reduction. The combined action of Yb and Ag on the photocatalytic effect of methyl orange in visible light was studied. The results show that Yb3+ did not affect the reduction of Ag+ in the synthetic process, and Ag did not affect the substitution of Yb3+ for Ti4+ into the lattice of anatase phase TiO2. The introduction of Yb created impurity energy levels in the TiO2 band gap, which broadened the light absorption range and shortened the band gap width. At the same time, the Ag with strong electron conduction ability improved the carrier transfer speed. Benefitting from the combined action of Yb and Ag, the photo‐degradation efficiency of Yb−Ag@TiO2HS on methyl orange in visible light was significantly improved compared with that of undoped, Yb‐doped and Ag‐loaded TiO2HS. The degradation efficiency of Yb−Ag@TiO2HS on methyl orange was 7 times, 3 times and 4 times higher than that of TiO2HS, Yb@TiO2HS and Ag@TiO2HS, respectively.