本文選題：層狀鈮酸鹽 + 聚合-絡(luò)合法�。� 參考：《安徽理工大學(xué)》2015年碩士論文

【摘要】：本文采用聚合-絡(luò)合法合成層狀鈮酸鹽KNb3O8,經(jīng)過離子交換、剝離組裝、復(fù)合等方法對其進(jìn)行改性處理,制備了TiO2/Nb3O8和ZrO2/Nb3O8納米復(fù)合功能材料。ZrO2/Nb3O8經(jīng)硫酸浸漬后,得到超強(qiáng)酸SO42--ZrO2/Nb3O8材料。選用高分辨透射電子顯微鏡(HRTEM)、X-射線衍射(XRD)、激光拉曼光譜(LRS)、傅里葉變換紅外光譜(FT-IR)、氨氣吸附程序升溫?zé)崦摳?NH3-TPD)等技術(shù)對催化劑的物理化學(xué)性質(zhì)進(jìn)行表征。使用液相紫外技術(shù)和氣相色譜技術(shù)分別考察了樣品降解亞甲基藍(lán)的光催化性能和對甲苯硝化反應(yīng)的酸催化性能。 結(jié)果顯示,采用聚合-絡(luò)合法制備的鈮酸鹽KNb3O8擁有較規(guī)整的層狀結(jié)構(gòu)。由于受層間水合質(zhì)子的影響,酸化后的樣品的XRD主晶面峰向小角移動。剝離重組后的樣品保留了部分層板結(jié)構(gòu),但樣品的結(jié)晶度明顯下降。TiO2/Nb3O8和ZrO2/Nb3O8復(fù)合材料在保留層狀主體的基礎(chǔ)上,表面也存在銳鈦礦型的Ti02晶體和四方相的Zr02晶體。 光催化降解亞甲基藍(lán)結(jié)果表明,前驅(qū)體層狀鈮酸鹽KNb3O8及其改性后的樣品對亞甲基藍(lán)均有較好的光降解效果。隨著層間離子(H+或K+)的變化,樣品的光催化性能變化不大。由于TiO2表面幾乎沒有酸性,而被降解物亞甲基藍(lán)是堿性的,Ti02對于降解物的吸附性能較差,故其光催化性能也較差。而納米片改性和納米微晶的復(fù)合改性提高了樣品的比表面積,提高了它們對亞甲基藍(lán)的吸附量,光催化效果也明顯增強(qiáng)。 甲苯定域選擇性硝化反應(yīng)結(jié)果表明,前驅(qū)體層狀鈮酸鹽和其改性后的樣品對于甲苯定域選擇性硝化反應(yīng)都有很好的酸催化效果。H+離子交換層間K+離子后,樣品的酸催化性能不好。這是由于HNb3O8的層間距太小,反應(yīng)物分子難以進(jìn)入層間與活性位點的質(zhì)子接觸。而納米片改性以及納米微晶的復(fù)合改性提高了樣品的比表面積、酸量和酸強(qiáng)度,故它們的酸催化效果較好。
[Abstract]:In this paper, layered niobate KNB _ 3O _ 8 was synthesized by polymerization-complexation method. It was modified by ion exchange, peeling and assembling, and ZrO2/Nb3O8 nano-composite functional material .ZrO _ 2 / NB _ 3O _ 8 was impregnated with sulfuric acid to obtain superacid SO42--ZrO2/Nb3O8 material. The physical and chemical properties of the catalysts were characterized by high resolution transmission electron microscopy (HRTEM), laser Raman spectroscopy (LRS), Fourier transform infrared spectroscopy (FTIR), and ammonia adsorption temperature programmed thermal desorption (NH3-TPD). The photocatalytic properties of methylene blue degradation and acid catalytic activity for nitration of toluene were investigated by liquid phase UV and gas chromatography, respectively. The results show that niobate KNb3O8 prepared by polymerization-complexation method has a regular layered structure. Due to the influence of interlaminar hydration proton, the peak of XRD main crystal plane of the acidified sample moves to small angle. After peeling and recombination, some laminar structures were retained, but the crystallinity of the samples decreased obviously. TIO _ 2 / NB _ 3O _ 8 and ZrO2/Nb3O8 composites had anatase Ti02 crystals and tetragonal Zr02 crystals on the surface. The photocatalytic degradation of methylene blue showed that the precursor layered niobate KNb3O8 and its modified samples had better photodegradation effect on methylene blue. With the change of interlayer ion H or K), the photocatalytic performance of the sample changed little. Because there is almost no acid on the surface of TiO2, and the degradation of methylene blue is alkaline, the adsorption performance of the degradation compound is poor, so its photocatalytic performance is also poor. The surface area of the samples was improved and the adsorption amount of methylene blue was increased, and the photocatalytic effect was also obviously enhanced by the nano-chip modification and the composite modification of nanocrystalline. The results of selective nitration of toluene show that both the layered niobate and the modified sample have good acid catalytic effect on the selective nitration of toluene. The acid catalytic performance of the sample is not good. This is due to the fact that the interlayer spacing of HNb3O8 is so small that it is difficult for reactant molecules to enter the interlaminar proton contact with active sites. However, the surface area, acid content and acid strength of the samples were improved by the nano-chip modification and the composite modification of nanocrystalline, so their acid catalytic effect was better.
【學(xué)位授予單位】：安徽理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：O643.36;TB383.1

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