Preparation of Ag-Modified (B,P)-Codoped TiO2 Hollow Spheres with Enhanced Photocatalytic Activity.

A series of TiO2 hollow sphere catalysts with or without nonmetal (B,P) dopants and Ag-modification were prepared through a sol-gel process with styrene-methyl methacrylate copolymer (PSMMA) microspheres as the template. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), laser Raman spectroscopy (LRS), and UV/Vis diffuse reflectance spectroscopy (UV/Vis DRS), and their photocatalytic activities were evaluated by degradation of methylene blue (MB). Both B and P dopants could narrow the band gap of the TiO2 catalyst, and the loaded Ag only played the role of photoelectron transmitter. The two effects of the nonmetal dopants and the loaded Ag improved the photocatalytic activity of the TiO2 hollow spheres. Moreover, the hollow sphere structure and oxygen vacancies were beneficial to photocatalysis. Among all the catalysts prepared, Ag-modified (B,P)-codoped TiO2 hollow spheres exhibited the highest photocatalytic activity. [ABSTRACT FROM AUTHOR]