The Phase Transition Process Of Cu, Y Doping And Co-doped Nano-TiO 2 Was Prepared By Sol-gel Method

In this paper,Cu doped TiO₂,Y doped TiO₂,Cu and Y codoped TiO₂ were prepared by sol-gel method.By means of X ray diffraction?XRD?,transmission electron microscopy?TEM?,X ray photoelectron spectroscopy?XPS?and ultraviolet visible spectrophotometer?Uv-Vis?measurements of different doping ions,different doping ion content and calcination temperature of TiO₂ phase,morphology,size and chemical state and absorption spectrum analysis.The main draw the following conclusions:?1?Y-doped TiO₂ nanopowders,the phase transition temperature of the anatase phase transition to rutile?A?R?is around 550?,and the phase transition temperature range is wide,about 550??850?,While the TiO₂ phase transition at 550? has been basically completed,indicating that Y doping inhibition of TiO₂ phase transition,and broaden the phase transition temperature range.With the increase of the sintering temperature,a significant second phase Y₂Ti₂O₇ appeared at 850 ?.The doping of Y will hinder the grain growth of grain TiO₂,and the grain size of Y-doped TiO₂ nanopowders will increase with the increase of temperature.TEM shows that the particle size of the powder is basically consistent with the XRD calculation.The content of adsorbed oxygen in the lattice of Y-doped TiO₂ nanopowders decreases with the increase of temperature,while Ti3+ increases with the temperature increasing.According to the Y3d content,Y is partially doped into the TiO₂ lattice.The doped Y ions are present in the lattice in the form of Y3 ?.Compared with undoped TiO₂,Y-doped TiO₂ light-absorbing band was blue-shifted.With the increase of the amount of Y,the light absorption band of the sample was blue-shifted,and the absorption band was red-shifted with the temperature increasing.?2?Cu-doped TiO₂ nanopowders,the phase transition of anatase phase rutile to rutile?A?R?transition temperature is around 550??600?.Compared with Cu-doped TiO₂ at 550?,the phase change of TiO₂ was basically completed at 550?,which indicated that Cu doping inhibited the transformation of TiO₂,but not significant.With the increase of the sintering temperature,the Cu oxide of Cu was present at 650 ?.Cu doping amount of 5%will hinder the TiO₂ anatase phase grain growth and doping amount of 3%does not inhibit grain growth.TEM shows that the particle size of the powder is basically consistent with the XRD calculation.The content of adsorbed oxygen in the lattice of Cu-doped TiO₂ nanopowders decreases with the increase of temperature.According to the Cu2p content,Cu was partially doped into the TiO₂ lattice.The doped Cu ions are present in the lattice in the form of Cu1+.Compared with undoped Tio2,Cu-doped TiO₂ light absorption band was red-shifted significantly.And with the increase of Cu content,the light absorption of the sample is larger than that of the low doping amount.With the increase of temperature,the sample UV-visible spectrum absorbs the band redshift.?3?Cu,Y co-doped TiO₂ nanopowders,the phase transition of anatase to rutile to transition?A?R?is near 650??700?.Compared with the temperature of Cu-doped TiO₂ and Y-doped TiO₂,the temperature of co-doped TiO₂ phase transition is between the two,which is the result of Cu and Y synergistic effect.With the increase of sintering temperature,the Cu oxide of Cu increases,indicating that the temperature will precipitate element Cu,but no Y₂Ti₂O₇ phase appears.HRTEM shows that CuO appears on the surface of TiO₂ particles.The content of adsorbed oxygen in the lattice of Cu-doped TiO₂ nanopowders decreases with the increase of temperature.Ti is present in the lattice in the form of Ti4+.According to the Cu2p content,Cu was partially doped into the TiO₂ lattice.The Cu ions are present in the lattice in the form of Cu2+ and Cu1+,Cul+ is decreasing and Cu2+ is increasing with the increase of temperature.Compared with undoped Ti2h doped with TiO₂,the red absorption of TiO₂ doped with Cu and Y was significant.And with the increase of temperature,the sample UV-visible spectrum absorption band redshift.