Nitrogen and Fluorine Codoped, Colloidal TiO₂ Nanoparticle: Tunable Doping, Large Red-Shifted Band Edge, Visible Light Induced Photocatalysis, and Cell Death

Abstract

Visible light photocatalysis by TiO requires efficient doping of other elements with red-shifted band edge to the visible region. However, preparation of such TiO with tunable doping is challenging. Here we report a method of making nitrogen (N) and fluorine (F) codoped TiO nanoparticle with tunable doping between 1 and 7 at. %. The preparation of N, F codoped TiO nanoparticle involves reaction of colloidal TiO nanorods with an ammonium fluoride-urea mixture at 300 °C, and the extent of N/F doping is tuned by varying the amount of ammonium fluoride-urea and the reaction time. Resultant colloidal N, F codoped TiO nanoparticles show doping dependent shifting of the band edge from the UV to near-IR region, visible light induced generation of reactive oxygen species (ROS), and visible light photodegradation of bisphenol A. A colloidal form of doped TiO nanoparticle offers labeling of cells, visible light induced ROS generation inside a cell, and successive cell death. This work shows the potential advantage of anisotropic nanoparticle precursor for tunable doping and colloidal form of N, F codoped TiO nanoparticle as a visible light photocatalyst.

Nickel and sulfur codoped TiO2 nanoparticles for efficient visible light photocatalytic activity

“…Codoping has been shown to increase the specific area of the surface, enhance the visible light absorption, and prolong the lifespan of photogenerated charging carriers. Based on data published the use of metal-nonmetal co-doping could significantly improve the photocatalytic activity [32,33].…”

One‐step solvothermal synthesis of hollow Bi2WO6 photocatalyst

“…It can be seen from Figure that the forbidden band width of the modified BWO‐2 sample was 2.74 eV, which was smaller than the forbidden band width of 2.83 eV of the unmodified BWO‐1, and the corresponding light absorption edge was also increased from 438 to 452 nm. The results show that the band gap of Bi 2 WO 6 was narrowed by KCl and PVP modification, and the absorption edge was significantly red‐shifted in the long wavelength direction, which increased the light absorption rate and further increased the photocatalytic activity …”

Structure regulation and photocatalytic activity enhancement of Bi2WO6by “double‐effect modification” mode

“…The Eg of Cl‐doped Bi 2 WO 6 was significantly smaller, indicating that the bandgap of Bi 2 WO 6 doped by Cl is narrower. The absorption edge increases from 435 to 455 nm, which has a significant red shift, and the modified Bi 2 WO 6 can absorb visible light more effectively, thereby further improving its photocatalytic performance …”