Abstract

Nanosize TiO₂ doped with metallic ions including Ag⁺, Sb²⁺, Ni²⁺ , Co²⁺, and Ce³⁺ powders were prepared by sol–gel method. X-ray diffraction was used to confirm the phase composition of the powders. Hydrogen sensing characteristics of these samples were investigated. The first-principles approach of density functional theory (DFT) is used to study the density of state (DOS) of TiO₂-doping metallic ions. The results show that hydrogen sensing property of the TiO₂ was remarkably enhanced by adding Ag⁺, its sensitivity value is 3.6 to 200 ppm hydrogen at 360 °C. The DOS of Sb²⁺, Ni²⁺, Co²⁺ and Ce³⁺ doped-TiO₂ has not been changed obviously after adsorbing H atom, while the DOS of Ag⁺-doped TiO₂ has changed distinctly. The variety of the electronic structure of Ag⁺-doped TiO₂ cause the change of the conductance of the sensor, so the hydrogen sensing properties of TiO₂ can be enhanced by doping Ag⁺ ion.

Keyword: TiO₂; Sensitivity; DOS; Hydrogen

PACS classification codes: 07.07.Df

Article Outline

1. Introduction

2. Experiment

3. Result and discussion

3.1. Structural characterization

3.2. Gas sensing characteristics

3.3. Hydrogen sensing mechanism

4. Conclusion

Acknowledgements

References