TiO2 nanoparticles were prepared by directly forced hydrolysis of Ti（SO4）2.The effect of calcination temperature on crystalline phase,physical and chemical properties of resulted particles was also investigated.The ...TiO2 nanoparticles were prepared by directly forced hydrolysis of Ti（SO4）2.The effect of calcination temperature on crystalline phase,physical and chemical properties of resulted particles was also investigated.The results showed that the calcination temperature had dominant influence on crystalline phase,specific surface area and photocatalytic performance of the TiO2 particles.Below 600℃,high order TiO2 crystalline phase cannot be obtained,whereas,anatase phase with a particle size of 18 nm was obtained at 700℃.When the temperature increased to 800℃,only anatase phase presented.The presence of SO2-4 restrains the transformation of anatase to rutile,strengthens the ability against sintering.The catalyst calcined at 700℃ has optimal catalytic performance and the highest specific surface area.The photocatalytic decolorization percentages of methyl orange at 90 min and Rhodamine B at 60 min reached 98.4 and 99.8%,respectively.展开更多
LaF3 nanowires with high aspect ratios have been prepared via a low-temperature solvothermal method using LaCl3 and KF or NH4F as starting materials in absolute alcohol at 160 ℃ for 12 h. XRD pattern and TEM images s...LaF3 nanowires with high aspect ratios have been prepared via a low-temperature solvothermal method using LaCl3 and KF or NH4F as starting materials in absolute alcohol at 160 ℃ for 12 h. XRD pattern and TEM images show that the products are hexagonal structure with diameter of 80 nm and length up to 8 μm. The lanthanum sources played most important roles, reaction temperature and time also played important roles in the morphology control of final LaF3 products. The optimal conditions for ideal LaF3 nanowire are at a reaction temperature of 160 ℃ and reaction time for 14 h using LaCl3 and NH4F as starting materials. A possible formation mechanism for LaF3 nanowires is proposed.展开更多
文摘TiO2 nanoparticles were prepared by directly forced hydrolysis of Ti（SO4）2.The effect of calcination temperature on crystalline phase,physical and chemical properties of resulted particles was also investigated.The results showed that the calcination temperature had dominant influence on crystalline phase,specific surface area and photocatalytic performance of the TiO2 particles.Below 600℃,high order TiO2 crystalline phase cannot be obtained,whereas,anatase phase with a particle size of 18 nm was obtained at 700℃.When the temperature increased to 800℃,only anatase phase presented.The presence of SO2-4 restrains the transformation of anatase to rutile,strengthens the ability against sintering.The catalyst calcined at 700℃ has optimal catalytic performance and the highest specific surface area.The photocatalytic decolorization percentages of methyl orange at 90 min and Rhodamine B at 60 min reached 98.4 and 99.8%,respectively.
文摘LaF3 nanowires with high aspect ratios have been prepared via a low-temperature solvothermal method using LaCl3 and KF or NH4F as starting materials in absolute alcohol at 160 ℃ for 12 h. XRD pattern and TEM images show that the products are hexagonal structure with diameter of 80 nm and length up to 8 μm. The lanthanum sources played most important roles, reaction temperature and time also played important roles in the morphology control of final LaF3 products. The optimal conditions for ideal LaF3 nanowire are at a reaction temperature of 160 ℃ and reaction time for 14 h using LaCl3 and NH4F as starting materials. A possible formation mechanism for LaF3 nanowires is proposed.
