【作者】 兰允祥；

【导师】 何杰；

【作者基本信息】 安徽理工大学 ， 应用化学， 2010， 硕士

【摘要】 层状钛铌酸盐由于它的独特结构越来越引起人们的重视,由于其层间的阳离子具有可交换性,可以通过离子交换、柱撑或剥片重组的方式在层间引入某些功能元素离子或氧化物可调变禁带宽度及还原电位,以此调变其活性。使得其在吸附、传导、分离和催化等诸多领域具有明显的优点,近年来对层状化合物的研究主要集中在对层状化合物的改性以及其催化性能的研究。本文分别利用固相反应以及聚合配合法合成钛铌酸钾KTiNbO5粉末晶体。利用x-射线衍射(XRD)、紫外-可见漫反射光谱(UV-vis DRS)、扫描电镜(SEM)、高分辨透射电镜(HR TEM)等对催化剂进行表征。采用红外光谱技术考察了催化剂对甲烷气中乙硫醇吸附与光催化氧化性能对样品的光催化活性和结构进行了表征,结果表明：通过固相反应合成钛铌酸钾(KTiNbO5),具有较好的层状结构,经过Fe3+与Ce3+离子交换制备Fe0.33TiNbO5、Ce0.33TiNbO5。交换过程中层板保持较好。经过Fe3+与Ce3+离子交换后,吸收边红移,禁带宽度从3.5eV降低到2.89eV与2.26eV。骨架上的Nb06八面体相关吸收峰位置有较大的移动,而TiO6八面体中的O-Ti-O特征吸收基本不变。合成的钛铌酸钾对于乙硫醇没有较好的吸附以及没有光催化活性。同时Fe0.33TiNbO5对乙硫醇吸附作用不明显,同时光催化也没有较好的改善,而通过铈离子交换制取的改性的钛铌酸盐,在可见光照射下,就可以在吸附基础上进行光催化氧化乙硫醇为硫酸酯,这与在紫外光照射下结果相似。通过聚合—配合法合成具有规整纳米晶的钛铌酸钾(KTiNbO5),同时颗粒半径比固相反应合成的样品较小,较小的颗粒有利于吸附物在层间传质,经过Fe3+与Ce3+离子交换制备Fe0.33TiNb05、Ce0.33TiNbO5。交换过程中层板保持较好。禁带宽度从3.47eV降低到2.87eV与2.24eV。同时骨架上的Nb06八面体相关特征吸收有一定的移动,而Ti06八面体中的O-Ti-O特征吸收移动较小。用Fe3+离子交换改性的钛铌酸盐Fe0.33TiNbO5对乙硫醇吸附作用不明显,同时在可见光照射下,对甲烷气氛中的乙硫醇有较弱的光催化活性。而通过铈离子交换制取的改性的钛铌酸盐,在可见光照射下,就可以在吸附基础上进行光催化氧化乙硫醇,这与在紫外光照射下结果相似,因此合成的改性钛铌酸盐Ce0.33TiNbO5对光催化脱除甲烷气氛中的乙硫醇有较好的活性。图24表4参62更多还原

【Abstract】 Layered titanoniobate drew increasing attention due to its unique structure. It can be pillared、exfoliated or reorganized though ion-exchange because of the exchangeability of its layer cation. Some functional element ions or oxides were introduced into the interlayer region, which can change the band gap and surface vacancy-reduction potential to modulate its activity of the catalysts. So the layer material had obvious advantages and can be used in absorption, conduction, separation and catalysis fields. The study of layered compounds focused on the modifying of layered compounds and their catalytic properties by ion-exchanging recent years.The potassium titanoniobate (KTiNbO5) is prepared by solid reaction and polymerizable complex method, and prepared Fe0.33TiNbO5 and Ce0.33TiNbO5 relatively through Ce3+ and Fe3+ ion-exchange respectively. The feature of samples crystalline structure, spectral response characteristics and so on were characterized by means of powder X-ray diffraction (XRD), High resolution transmission electron microscope(HR TEM), UV-visible diffuse reflectance spectroscopy (UV-vis-DRS) and Fourier transform infrared spectroscopy (FT-IR).The results reveal that the layer potassium titanoniobate (KTiNbO5) are prepared through solid reaction method. The layer structure remains after Fe3+、Ce3+ ion-exchanging and the energy of band gap decreases from 3.5eV to 2.89eV and 2.26eV when Potassium ion are exchanged by Ferric ion or Cerium ion. The skeleton of the NbO6 octahedral absorption peaks blue-shift, the O-Ti-O band of TiO6 octahedral in characteristic absorption unchanged. The adsorption feature and photocatalytic oxidation activity for ethanethiol of potassium titanoniobate is weak. And the adsorption feature and photocatalytic oxidation activity for ethanethiol of the Fe1/3 TiNbO5 prepared through Fe3+ ion-exchanged is very weak, too. However, the titanoniobate ion-exchanged by Ce3+, under the visible light irradiation, the photocatalytic oxidation activity for ethanethiol of it after adsorption is strong, which is similar to under the UV light irradiation.The layer nanocrystalline potassium titanoniobate (KTiNbO5) are prepared through polymerizable complex method. The particle radius of potassium titanoniobates is smaller and the smaller particles are conducive to the adsorption and mass transfer in the layer. And prepared Fe0.33TiNbO5 and Ce0.33TiNbO5 relatively and the layer structure remains after Fe3+、Ce3+ ion-exchanging, and the energy of band gap decreases from 3.47eV to 2.87eV and 2.24eV when Potassium ion are exchanged by Ferric ion or Cerium ion. The absorption peaks of the skeleton of the NbO6 octahedral shifts, the O-Ti-O of TiO6 octahedral in characteristic absorption are unchanged. The adsorption feature and photocatalytic oxidation activity for ethanethiol of the Fe0.33TiNbO5 prepared through Fe3+ion-exchanged is very weak. But the titanoniobate ion-exchanged by Ce3+, under the visible light irradiation, the photocatalytic oxidation activity for ethanethiol of it after adsorption is strong, which is similar to under the UV light irradiation. So the photocatalytic oxidation activity of modified titanoniobate Ce0.33TiNbO5 is strong.Figure 24 table 4 reference 62更多还原