Facile Preparation of N/F Co-Doped Mesoporous TiO2 vis-Photocatalyst based on a Bi-Functional Template

Abstract

Developing nonmetal-doped mesoporous TiO2 is highly attractive for preparing semiconductor visible photocatalyst with high activities. Here, we prepare N/F co-doped mesoporous TiO2 with high vis-photocatalytic activities by a simple liquid phase deposition process followed by annealing in air using C[Formula: see text]TAB as a bi-functional template (forming mesoporous and providing dopants). N2 adsorption isotherms, low-angle X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicate the formation of wormhole-like mesoporous structure. Wide-angle XRD and high-resolution TEM demonstrate the presence of anatase TiO2 mesopore wall. XPS analyses reveal that N is doped into TiO2 lattice in the forms of substitutional and interstitial N species, and that F is doped into the TiO2 lattice in the form of interstitial F. The mesopore-forming and doping mechanisms are thoroughly discussed based on the bi-function of C[Formula: see text]TAB template. Mesoporous structure results in a high BET surface area of TiO2. High-concentration nitrogen species in anatase lattice and mesoporous structure remarkably increase the visible absorption of TiO2. As a result, the reaction rate constant of MB degradation catalyzed by N/F co-doped mesoporous TiO2 photocatalysts is about 7 times that by P25.