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Fabrication of Predominantly Mn 4+ ‐Doped TiO 2 Nanoparticles under Equilibrium Conditions and Their Application as Visible‐Light Photocatalyts
Author(s) -
Wang Lijie,
Fan Jiajie,
Cao Zetan,
Zheng Yichao,
Yao Zhiqiang,
Shao Guosheng,
Hu Junhua
Publication year - 2014
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201402114
Subject(s) - dopant , x ray photoelectron spectroscopy , manganese , materials science , doping , photocatalysis , chemical state , band gap , valence (chemistry) , titanium , inorganic chemistry , analytical chemistry (journal) , chemical engineering , chemistry , optoelectronics , metallurgy , catalysis , biochemistry , organic chemistry , chromatography , engineering
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 TiO 2 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.