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 semiconductors, as well as high interface area and porous structure of the heterojunction bilayer films. Charge separation between Bi2WO6 (underlayer) and TiO2 (overlayer) was verified by photoluminescence (PL) and current−voltage (I−V) characteristics studies.

A novel and environmental friendly method was developed to prepare transparent, uniform, crack-free and visible light activated nitrogen doped (N-doped) titania thin films without the use of organic Ti precursors and organic solvents. The N-doped titania films were prepared from heating aqueous peroxotitanate thin films deposited uniformly on superhydrophilic uncoated glass substrates. The pure glass substrates were superhydrophilic after being heated at 500 degrees C for 1 h. Nitrogen concentrations in the titania films were adjusted by changing the amount of ammonia solution. The optimal photocatalytic activity of the N-doped titania films was about 14 times higher than that of a commercial self-cleaning glass under the same visible light illumination. The current reported preparative technique is generally applicable for the preparation of other thin films.

No abstract

No abstract

No abstract