Tio2 FeN

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 g4.3 indicates Fe³⁺ 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 TiO₂, 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 TiO₂ and Fe-doped TiO₂ 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 TiO₂ 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 NO_x

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 NO_x

4. Conclusions

Acknowledgements

References