Optical properties and photocatalytic activity of nanocrystalline TiO2 doped by 3d-metal ions

Abstract

The influence of impurities on optical and photocatalytic properties was studied in a series of nanocrystalline TiO 2 with similar coherent scattering region sizes, phase compositions, surface areas and lattice parameters doped by Fe, Cr, Mn and V ions. Doping leads to an increase of absorption in the visible part of the spectrum due to the formation of additional levels in the band gap. In the case of Fe and Cr ions, d-d transitions are observed, whereas in the case of Mn and V ions, an additional band is associated with the transition from impurity level to Ec. The presence of impurities effectively suppresses photocatalytic activity in the methyl orange decoloration reaction.

Hydrothermal Synthesis of Layered Titanium Phosphate Ti2O2H(PO4)[(NH4)2PO4]2 and Its Potential Application in Cosmetics

“…There are several approaches to suppressing the photocatalytic reactions on the surface of titania, including using amorphous titanium oxide, which has less photocatalytic activity than the crystalline phases [8]. Additionally, photocatalytic activity may be suppressed by doping the titanium oxide with metal ions [9][10][11] or modifying its surface composition [12][13][14]. Matsukura and Onoda showed that phosphate modification leads to photocatalytic activity suppression in TiO 2 -containing pigments [12].…”

Tailoring band gap and photocatalytic activity of ZnO via Cu doping for enhanced Congo Red degradation

“…Dopants may create energy levels inside the bandgap, which helps to separate electron-hole pairs created by light and increases the e ciency of redox processes. Therefore, the lack of these dopants in undoped ZnO results in a lower photocatalytic effectiveness compared to doped versions, as shown in several studies [35,36]. Finally, the creation of surface imperfections or areas that might trap charge carriers, although important for affecting the behaviour of charge carriers, may not be strong enough at lower levels of doping to have a major effect on catalytic activity.…”

Synthesis and characterization of zirconia nanorods as a photo catalyst for the degradation of methylene blue dye

“…9. In addition to particle size, phase composition, and optical characteristics, there may be other parameters that influence photocatalytic activity [32].…”