Structure and Photocatalytic Activity of $Ti_1_-_xM_xO_2_\pm_\delta$ (M = W, V, Ce, Zr, Fe, and Cu) Synthesized by Solution Combustion Method

The W, V, Ce, Zr, Fe, and Cu metal ion substituted nanocrystalline anatase $TiO_2$ was prepared by solution combustion method and characterized by XRD, Raman, BET, EPR, XPS, IR TGA, UV absorption, and photoluminescence measurements. The structural studies indicate that the solid solution formation was limited to a narrow range of concentrations of the dopant ions. The photocatalytic degradation of 4-nitrophenol under UV and solar exposure was investigated with $Ti_1_-_xM_xO_2_\pm_\delta$. The degradation rates of 4-nitrophenol with these catalysts were lesser than the degradation rates of 4-nitrophenol with undoped $TiO_2$ both with UV exposure and solar radiation. However, the photocatalytic activities of most metal ion doped $TiO_2$ are higher than the activity of the commercial $TiO_2$, Degussa P25. The decrease in photocatalytic activity is correlated with decrease in photoluminescence due to electron states of metal ions within the band gap of $TiO_2$