Synthesis of Porous and Visible-Light Absorbing Bi2WO6/TiO2 Heterojunction Films with Improved Photoelectrochemical and Photocatalytic Performances

This work reports the preparation of porous and visible-light absorbing Bi2WO6/TiO2 heterojunction films as a photoelectrode and their photoelectrochemical and photocatalytic performances. The Bi2WO6 underlayers with high surface roughness were prepared by a superhydrophilicity-assisted method. The Bi2WO6/TiO2 bilayer films showed high interface area between the Bi2WO6 and TiO2 layers. Significant enhancement in visible light photocurrent generation on the optimal Bi2WO6/TiO2 film was observed as compared with unmodified Bi2WO6 (a factor of 2) and unmodified TiO2 (a factor of 13) films. The optimal visible-light photocatalytic activity of the Bi2WO6/TiO2 film was 15.1 nm of stearic acid degraded, which was 6 and 4.6 times higher than that of unmodified Bi2WO6 and TiO2 films, respectively. The enhanced photoelectrochemical and photocatalytic performances of Bi2WO6/TiO2 films were attributed to the improved charge separation efficiency derived from the suitable valence band interaction between the two semic...