铁系纳米材料的制备及吸附与催化性能研究

发布时间：2018-06-30 09:28

本文选题：纳米粒子 + Fe3O4　；参考：《新疆大学》2015年硕士论文

【摘要】：铁系纳米材料是一种重要的过渡金属纳米材料,因其价格低廉、对环境友好、赋有磁性,在催化、气敏材料、靶向治疗、锂离子电池和磁性材料等领域具有潜在的应用。但和其他金属材料与贵金属相比,铁系纳米材料的缺点是其活性相对较低。由前人的研究表明,通过改变纳米材料的结构,控制纳米粒子的形貌,增大纳米粒子的比表面积等措施可提高其活性。因此,可以通过不同的设计与合成方法,制备出具有不同大小、组成、形貌、结构的铁系纳米材料,使其具有独特性质,从而将其应用于重要领域。本论文旨在采用合理的设计路线,通过溶剂热法、程序升温渗氮法、两相法以及熔融盐焙烧等方法,制备出不同结构和组成的铁系纳米材料,并对其性能进行了研究。论文主要研究成果如下:首先,采用溶剂热法得到Fe3O4纳米球,然后在磁性粒子表面通过原位生长过程,得到Fe3O4@Ni(OH)2核壳分层纳米材料,最后通过低温焙烧过程使Fe3O4@Ni(OH)2前驱体分解为磁性Fe3O4@NiO核壳结构纳米材料。制得的产物用X射线粉末衍射(XRD)、元素分析(EDS)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)进行了表征。TEM结果表明Fe3O4磁心直径约为250 nm,NiO壳层厚度约为30 nm。将Fe3O4@NiO核壳结构纳米粒子作为磁性可分离的吸附剂,用于刚果红(CR)染料的吸附,结果表明,对CR的最大吸附容量可达128.9 mg/g。此外,将Fe3O4@NiO纳米粒子用于催化苯乙烯环氧化反应,也展现了非常优异的催化性能,其中选择性、转化率和产率分别可达到100%,99%,99%。制得的Fe3O4@NiO催化剂也具有良好的循环性能,在外加磁场下很容易被回收利用,经过5次循环后,其催化活性并未明显降低。其次,通过对FeCl3·6H2O强迫水解得到梭形?-FeOOH纳米粒子,并以此为前驱体,经过正硅酸乙酯氨解包硅后得到?-FeOOH@SiO2纳米材料,再通过程序升温渗氮法得到混合有Fe、Fe3N、Fe4N物相的磁性FexNy@SiO2核壳结构纳米粒子。此外,直接将?-FeOOH前驱体氮化、用碱液刻蚀FexNy@SiO2表面硅层、修改后氮化方法,还制得了不同尺寸和形貌的微米氮化铁粒子(M-FexNy)、纳米氮化铁粒子(N-FexNy)和微米氮化四铁粒子(Fe4N)。将得到样品用于苯乙烯环氧催化反应,实验结果表明FexNy@SiO2核壳结构纳米粒子表现出优异的催化性能,且容易分离和回收。对FexNy@SiO2纳米粒子进行了循环性能实验,在循环5次后,其对苯乙烯环氧的催化性能也未明显降低。最后,以梭形?-FeOOH纳米粒子为前驱体,通过两相法及不同温度熔融盐焙烧法得到两种磁性可分离的Fe3O4/C纳米材料。对产物进行了XRD、EDS、TEM等表征,结果表明合成的Fe3O4纳米粒子近似球形,直径约100 nm,且均匀地负载在碳膜上。将两种Fe3O4/C纳米复合物用于吸附CR性能研究,实验结果表明,两者均有较好的吸附性能,对刚果红的最大吸附容量分别为107.1 mg/g和94.8 mg/g。通过对吸附结果的线性拟合,表明两种吸附剂对CR的吸附过程均较好的符合Langmuir吸附模型。而且,这种磁性纳米复合材料也展现了很好的磁可分离特性,在水处理方面拥有潜在的应用前景。
[Abstract]:Iron based nanomaterials are one of the most important transition metal nanomaterials. They have potential applications in the fields of catalysis, gas sensitive materials, targeting therapy, lithium ion batteries and magnetic materials because of their low price, environment friendly and magnetic properties. But compared with other metal materials and precious gold, the disadvantages of the iron based nanomaterials are their relative activity. It has been shown by previous studies that by changing the structure of nanomaterials, controlling the morphology of nanoparticles and increasing the specific surface area of the nanoparticles, the activity of the nanoparticles can be improved. Therefore, iron based nanomaterials with different sizes, composition, shape and structure can be prepared by different design and synthesis methods, so that they have unique properties. The purpose of this paper is to apply it to important fields. The purpose of this paper is to prepare iron based nanomaterials with different structures and compositions by means of solvothermal method, temperature programmed nitriding, two-phase method and molten salt roasting. The main research results of this paper are as follows: first, solvothermal method is used. The Fe3O4 nanospheres were obtained, then the Fe3O4@Ni (OH) 2 nuclear shell layered nanomaterials were obtained on the surface of the magnetic particles. Finally, the Fe3O4@Ni (OH) 2 precursor was decomposed into magnetic Fe3O4@NiO nuclear shell nanostructures by the process of low temperature calcination. The obtained products were obtained by X ray powder diffraction (XRD), elemental analysis (EDS), and scanning electron display. Micromirror (SEM) and transmission electron microscopy (TEM) were used to characterize.TEM. The results showed that the diameter of Fe3O4 core was about 250 nm, and the thickness of NiO shell was about 30 nm., and Fe3O4@NiO core shell nanoparticles were used as magnetic separable adsorbents for the adsorption of Congo red (CR) dyes. The results showed that the maximum adsorption capacity of CR was 128.9 mg/g.. Fe3O4@NiO nanoparticles are used to catalyze the epoxidation of styrene, and also exhibit excellent catalytic properties. The selectivity, conversion and yield can reach 100%, 99%, and 99%., respectively. The Fe3O4@NiO catalyst also has good cycling performance. It is easy to be recycled under the applied magnetic field. After 5 cycles, the catalytic activity of the catalyst is improved. Second, the fusiform -FeOOH nanoparticles were obtained by forced hydrolysis of FeCl3. 6H2O, which was used as precursor and obtained by ammonia solution of tetraethyl orthosilicate to obtain -FeOOH@SiO2 nanomaterials, and then the magnetic FexNy@SiO2 core shell structure nanoparticles mixed with Fe, Fe3N and Fe4N phase were obtained by the method of temperature programmed nitriding. -FeOOH precursor nitridation, etching FexNy@SiO2 surface silicon layer with alkaline solution, modified nitriding method, and making different sizes and morphologies of micron iron nitride particles (M-FexNy), nano iron nitride particles (N-FexNy) and micron nitriding four iron particles (Fe4N). The catalytic reaction of the samples to styrene epoxy will be obtained. The experimental results show that the FexNy@SiO2 core shell is used. The structure nanoparticles showed excellent catalytic performance and easy to be separated and recovered. The cyclic properties of FexNy@SiO2 nanoparticles were tested. After 5 cycles, the catalytic properties of styrene epoxy were not significantly reduced. Finally, the spindle shape -FeOOH nanoparticles were used as precursors, and the two phase method and different temperature molten salt roasting method were obtained. Two kinds of Magnetic Separable Fe3O4/C nanomaterials were obtained. The products were characterized by XRD, EDS and TEM. The results showed that the synthesized Fe3O4 nanoparticles were approximately spherical, about 100 nm in diameter and uniformly loaded on the carbon film. Two kinds of Fe3O4/C nanocomposites were used to adsorb CR properties. The experimental results showed that both of them had good adsorption properties, and the results showed that both of them had good adsorption properties. The maximum adsorption capacity of Congo red is 107.1 mg/g and 94.8 mg/g. respectively through the linear fitting of the adsorption results. It shows that the adsorption process of two adsorbents to CR is better in conformity with the Langmuir adsorption model. Moreover, the Magnetic Nanocomposites also exhibit good magnetic separation properties and have potential applications in water treatment. View.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

【共引文献】