كنترل خواص فيزيكي و حسگري گاز نانوساختار دي اكسيد تيتانيم به كمك فاز ثانويه اكسيد اربيم

Controlling physical and sensing properties of nanostructured titanium dioxide by erbium oxide

Nanocrystalline and mesoporous Ti02-Er203 films and powders with various Ti02:Er203 molar ratios have been prepared by a sol-gel route. X-ray diffraction and Fourier transform infrared spectroscopy revealed that erbium oxide formed in the range 50-100 mol.-%Er203, whereas erbium dititanate formed in the range 25-100 mol.-%Er203. Oxygen deficient titania phases (Ti02-x), such as Ti7013 and Ti203, were observed for Ti02:Er203=25:75 (molar ratio) system annealed at 800°C. It was observed that Er203 retarded anatase to rutile transformation. Furthermore, TEM analysis also showed that Er203 hindered the crystallisation and crystal growth of powders. Atomic force microscope (AFM) analysis confirmed that TiO^E^O^S^ (molar ratio) system annealed at 600°C produced the smallest grain size (17 nm) and the highest roughness. Moreover, Ti02:Er203=50:50 (molar ratio) system annealed at 800°C showed the smallest grain size (32 nm) and the highest roughness. The sensing properties of Ti02 films were improved by introducing Er203 phase into the sensing film. The fabricated sensors showed stable, reliable and reproducible response with small response and recovery times towards CO and N02 gases. The working temperature of the sensors was reduced down to 200°C, and therefore they can be used for industrial application.