Decorated TiO2 Nanoparticles with La and Ag Elements to Improve Photocatalytic Activity Under Visible Light for the Degradation of MO.

Visible-light photocatalyst of TiO2/La/Ag nanocomposites were successfully synthesized via the conventional sol-gel method and reducing agent of Ag+. The photocatalytic activities were evaluated by methyl orange (MO) degradation. They have remarkable photocatalytic activities compared to TiO2-Anatase, which is thanks to the separation of electron-hole pairs by Ag nanoparticles and lanthanum. The products were characterized by a series of techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and Uv-vis. The results show that spherical nanocomposites have been prepared with the size 300 nm and Ag nanoparticles (~10 nm) are dispersed uniformly onto the surface of TiO2/La, which forms TiO2/La/Ag nanocomposites. TiO2/La/Ag nanocomposites have good absorption in the visible region (700 nm > λ > 400 nm). The reasons are as follows: (1) the efficient separation of photogenerated electrons and holes of the photocatalysts on the surface of TiO2/La/Ag nanocomposites and (2) a wide visible-light photoabsorption range (700 nm > λ > 400 nm). Therefore, this study may provide some new idea for the rational design and the facile synthesis of composite catalysts with a green, efficient pathway.