Fabrication of predominantly Mn4+ -doped TiO2 nanoparticles under equilibrium conditions and their application as visible-light photocatalyts.
The chemical state of a transition-metal dopant in TiO(2) can intrinsically determine the performance of the doped material in applications such as photocatalysis and photovoltaics. In this study, manganese-doped TiO2 is fabricated by a near-equilibrium process, in which the TiO(2) precursor powder precipitates from a hydrothermally obtained transparent mother solution. The doping level and subsequent thermal treatment influence the morphology and crystallization of the TiO(2) samples. FTIR spectroscopy and X-ray photoelectron spectroscopy analyses indicate that the manganese dopant is substitutionally incorporated by replacing Ti(4+) cations. The absorption band edge can be gradually shifted to 1.8 eV by increasing the nominal manganese content to 10 at %. Manganese atoms doped into the titanium lattice are associated with the dominant 4+ valence oxidation state, which introduces two curved, intermediate bands within the band gap and results in a significant enhancement in photoabsorption and the quantity of photogenerated hydroxyl radicals. Additionally, the high photocatalytic performance of manganese-doped TiO(2) is also attributed to the low oxygen content, owing to the equilibrium fabrication conditions. This work provides an important strategy to control the chemical and defect states of dopants by using an equilibrium fabrication process.
School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450002 (P.R. China); International Joint Research Laboratory for Low-Carbon & Environmental Materials of Henan Province, Zhengzhou University, Zhengzhou 450002, Henan Province (P.R. China).
Lijie
L
Wang
Jiajie
J
Fan
Zetan
Z
Cao
Yichao
Y
Zheng
Zhiqiang
Z
Yao
Guosheng
G
Shao
Junhua
J
Hu
D064753:Ammonium Hydroxide / Q000737:chemistry; D002384:Catalysis; D005453:Fluorescence; D017665:Hydroxyl Radical / Q000737:chemistry; D008027:Light; D008345:Manganese / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D010777:Photochemistry / Q000379:methods*; D056951:Photoelectron Spectroscopy; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
C009495:titanium dioxide; D017665:Hydroxyl Radical; D008345:Manganese; D064753:Ammonium Hydroxide; D014025:Titanium; D010100:Oxygen
doping; manganese; nanoparticles; photochemistry; titanates