Rational Electron Transmission Structure in an Ag2O/TiO2(anatase-B) System for Effective Enhancement of Visible Light Photocatalytic Activity

Titanium dioxide has received great attention as a photocatalyst. However, due to the relatively large bandgap energy of TiO 2 and fast recombination of photogenerated electron–hole pairs, various attempts have been made to improve its photocatalysis, including reasonable energy band construction for broadening light absorption and effectively separating photogenerated electron–hole pairs. In this work, a reasonable energy band construction is realized by an Ag 2 O/TiO 2 (anatase-B) heterostructure system. The Ag 2 O/TiO 2 (anatase-B) microspheres aggregated by radially aligned nanosheets are synthesized by a one-step sol–gel solvothermal method. The Ag 2 O nanoparticles are uniformly coated on TiO 2 (anatase-B) microspheres with a diameter of 2.5–4.5 μm. Compared with P25 and TiO 2 (anatase-B), the photocatalytic activity of the Ag 2 O/TiO 2 (anatase-B) heterostructure is obviously enhanced under visible-light irradiation with the degradation of methyl orange. The photocatalytic mechanism of Ag 2 O/TiO 2 (anatase-B) microspheres is proposed. Four different ways of photoelectron transportation is apparently involved in the photodegradation. This work demonstrates that reasonable energy band construction by a three-component heterostructure not only favors visible light harvesting but also promotes the separation of photogenerated electron–hole pairs.