来源:百度文库 编辑:神马文学网 时间:2024/04/20 20:43:04
Abstract
Nitrogen substituted yellow colored anatase TiO
2−xN
x and Fe–N co-doped Ti
1−yFe
yO
2−xN
x have been easily synthesized by novel hydrazine method. White anatase TiO
2−δ and N/Fe–N-doped samples are semiconducting and the presence of ESR signals at g
1.994–2.0025 supports the oxygen vacancy and g
4.3 indicates Fe
3+ in the lattice. TiO
2−xN
x has higher conductivity than TiO
2−x and Fe/Fe–N-doped anatase and the UV absorption edge of white TiO
2−x extends in the visible region in N, Fe and Fe–N co-doped TiO
2, which show, respectively, two band gaps at
3.25/2.63,
3.31/2.44 and 2.8/2.44 eV. An activation energy of
1.8 eV is observed in Arrhenius log resistivity vs. 1/T plots for all samples. All TiO
2 and Fe-doped TiO
2 show low 2-propanol photodegradation activity but have significant NO photodestruction capability, both in UV and visible regions, while standard Degussa P-25 is incapable in destroying NO in the visible region The mid-gap levels that these N and Fe–N-doped TiO
2 consist may cause this discrepancy in their photocatalytic activities.
Article Outline
- 1. Introduction
- 2. Experimental
- 2.1. Synthesis
- 2.1.1. Preparation of titanium hydroxide, oxalate and their hydrazinates
- 2.1.2. Preparation of iron containing titanium oxalates and their hydrazinates
- 2.2. Characterization
- 2.3. Photodegradation of aqueous 2-propanol and gaseous NOx
- 2.4. Thermal products of the hydroxide, oxalate and their hydrazinates: codes
- 3. Results and discussions
- 3.1. Anatase phase: Fe-doped TiO2
- 3.2. BET surface area, nitrogen content, ESCA and DRS: band gap
- 3.2.1. Nitrogen: O2–N2 analysis and XPS
- 3.2.2. Diffuse reflectance spectra (DRS)
- 3.3. DC electrical conductivity, ESR
- 3.3.1. Electron spin resonance (ESR)
- 3.3.2. Mechanism of conductivity
- 3.3.3. Impurity levels in the wide band gap TiO2
- 3.3.4. Photocurrent
- 3.4. Photo-oxidation of 2-propanol and photodestruction of NOx
- 4. Conclusions
- Acknowledgements
- References