Enhanced Visible Light Photocatalytic Activity for TiO<sub><b>2</b></sub> Nanotube Array Films by Codoping with Tungsten and Nitrogen

<table>FESEM cross-sectional views of W and N codoped TiO<sub>2</sub> nanotube arrays: (a) N-TiO<sub>2</sub>, (b) W-N-TiO<sub>2</sub>-1.</table>

International Journal of Photoenergy

Figure 2: Enhanced Visible Light Photocatalytic Activity for TiO<sub><b>2</b></sub> Nanotube Array Films by Codoping with Tungsten and Nitrogen 