【作者】 张蕾；

【导师】 俞泽民；

【作者基本信息】 哈尔滨理工大学 ， 材料加工工程， 2010， 硕士

【摘要】 本文以钛酸丁酯为钛源,无水乙醇为溶剂,采用溶胶-凝胶法,制备TiO₂纳米粉;然后以硝酸铁引入掺杂元素Fe,制备了单一锐钛矿结构的(Ti_1-xFe_x)O₂纳米粉;再以硝酸镧引入La元素,制备单一锐钛矿结构的（Ti1-x-yFexLay）O2纳米粉。采用TG-DTA、XRD、SEM、分光光度计等分析测试方法,测试凝胶的热行为;粉体的结构、微观形貌及光催化性能;进而研究制备工艺对TiO₂粉体的结构、微观形貌及其光催化性能的影响,试验结果研究表明:在本试验条件下,350℃⁵50℃合成的未掺杂产物均为单一的锐钛矿型TiO₂,合成温度达到650℃时,23.6%的锐钛矿相转变为金红石相。随着合成温度的升高,TiO₂纳米粉的平均晶粒尺寸与颗粒尺寸都逐渐增大。650℃时小尺寸颗粒已基本消失,团聚程度逐渐降低。此时合成的混晶型TiO₂光催化活性最好,对甲基橙的降解率达到51%。650℃合成的(Ti_1-xFe_x)O₂（x=0.01%,0.03%,0.05%）纳米粉,均为单一的锐钛矿相,Fe³⁺离子掺杂抑制了锐钛矿相向金红石相的转变。随着Fe³⁺离子掺杂浓度x逐渐提高,粉体的平均晶粒尺寸先增大后减小,与未掺杂TiO₂相比明显细化;颗粒尺寸明显减小,小尺寸颗粒占主体;团聚现象有所改善,颗粒形态多元化。当Fe³⁺离子掺杂浓度为x=0.03%时粉体的平均晶粒尺寸最小,为5.497nm;对甲基橙的降解率为87.5%,光催化活性最好,比未掺杂TiO₂粉体提高了36.5%。650℃合成的（Ti1-x-yFexLay）O2纳米粉（x+y=0.03%, y/x=1/5,1/2,5/1,6/0）也均为单一的锐钛矿结构TiO₂,Fe³⁺、La³⁺复合掺杂也同样抑制了TiO₂由锐钛矿相向金红石相的转变。随着镧铁摩尔比y/x逐渐提高,粉体的平均晶粒尺寸、颗粒尺寸都有不同程度细化,粒度分布均匀,团聚现象更为严重。La³⁺、Fe³⁺复合掺杂后,(Ti_1-x-yFe_xLa_y)O₂纳米粉的光催化活性显著提高,当y/x=1/2时,光催化活性最高,比未掺杂的提高了41%。更多还原

【Abstract】 In this paper, sol-gel method was used to prepare TiO₂ nano-powder when n-butyl titanate was used as titanium source and anhydrous ethanol as solvent; and then the introduction of Fe dopping elements was from ferric nitrate to prepare (Ti_1-xFe_x)O₂ nano-powder with single anatase structure; and then lanthanum nitrate was used as the re-introduction of La dopping element to prepare (Ti_1-x-yFe_xLa_y)O₂ nano-powder with single anatase structure. TG-DTA, XRD, SEM, spectrophotometer and other modern analytical methods were used to test the thermal behavior of the gel; the structure, morphology and photocatalytic properties of the powder; The influence of preparation process on the structure, morphology and photocatalytic properties of TiO₂ nano-powder were studied. The test result found:In this experimental conditions, the undopped products synthesized within the limit of 350℃ 550℃are single anatase TiO₂; When the synthetic temperature reaches 650℃, there are 23.6 percent of the anatase phase transformed into rutile phase. With the synthetic temperature gradually increasing, the average grain size and the particle size of the TiO₂ nano-powder gradually increased. As the synthetic temperature reaches 650℃, the small-size particles have basically disappeared and the reunion levels gradually decreased, TiO₂ nano-powder of mixed crystal type has the best photocatalytic property, at the moment, the degradation rate of methyl orange is 51 percent.(Ti_1-xFe_x)O₂（x= 0.01%, 0.03%, 0.05%） nano-powder synthesized at 650℃are all in the form of single anatase phase, iron-dopping inhibited the transformation of anatase phase into rutile phase. With the molar dosage concentration of Fe3+ ion x gradually increasing, the average grain size of the (Ti_1-xFe_x)O₂ nano-powder firstly increased and then decreased, there is significantly refinement comparing with non-dopped TiO₂ nano-powder; and the particle size also significantly reduced at the monment small size of particles are in the dominance and the reunion phenomenon improved with morphology diversity of the particle. When the iron ion dosage concentration x is 0.03 percent, the average grain size of the powder are 5.497nm coming up to the smallest and the degradation rate of methyl orange is 87.5 percent at the best photocatalytic property 36.5 percent better than the non-dopped TiO2 nano-powder.When the ion dosage concentration sum of the Fe³⁺ and La³⁺ is 0.03 percent, (Ti_1-x-yFe_xLa_y)O₂（x+y=0.03%; y/x=1/5, 1/2, 5/1, 6/0） nano-powders synthesized at 650℃are also the TiO2 of single anatase structure, co-dopping with Fe³⁺ and La³⁺ ion could also inhibited the transformation of anatase phase into rutile phase. With the La³⁺ and Fe³⁺ ion co-dopping concentration molar ratio y/x gradually increasing, the average grain size and the particle size both have more obviously refinement in different degree as the uniform particle size is in distribution and the agglomeration even more seriously. After the La³⁺ ion co-dopped with Fe³⁺ ion, the photocatalytic property of (Ti_1-x-yFe_xLa_y)O₂ nano-powder significantly increased. With the co-dopping concentration molar ratio y/x comes up to 1/2, the photocatalytic property of (Ti_1-x-yFe_xLa_y)O₂ nano-powder 41 percent better than undopped nano-powder.更多还原