铁酸镍的合成、改性及其光热催化性能研究

发布时间：2018-04-15 17:34

本文选题：铁酸镍 + 氧空位　；参考：《上海应用技术大学》2017年硕士论文

【摘要】：人类活动导致大气中CO2浓度越来越高,温室效应已经对环境产生了严重的影响。因此寻找一种可以解决CO2气体污染的方法已经成为世界热点话题。在众多备选方案中,利用催化剂在光热条件下催化转化CO2为碳氢化合物成为一个可行性高、易于实现的方法。这一方法不仅可以降低大气中的CO2含量从而解决环境污染问题,而且其反应产物为易储存的化学燃料,可以缓解目前世界资源短缺问题。铁酸盐材料的价格低廉,制备工艺简单,在CO2催化还原领域中是研究者重点关注的材料之一。因此,本篇论文围绕性能最佳的铁酸镍展开,利用多种方法对其进行改性,力求得到具有极致催化性能的新型催化材料。详细科研工作及成果如下三个部分:1.高氧空位浓度铁酸镍催化剂的制备及其光热催化性能研究利用溶剂热方法,乙二醇作为表面活性剂,通过调节前驱体溶剂中的乙二醇比例来调节铁酸镍催化剂的氧空位含量,探究催化剂中氧空位的浓度与光热催化效率的内在关系,研究具有氧缺陷铁酸镍的热催化反应机理,以及表面活性剂在溶剂热法合成催化剂时对催化剂晶相结构的影响。带有氧空位的铁酸盐具有高的裂解二氧化碳和水的能力,有制备工艺简单易操作、原料低价等优点。而且高浓度的氧空位不仅作为缺陷中心,在价带附近创造了杂质能级,并诱导带隙变窄。这使得含有氧空位的金属氧化物催化剂可以进行光催化用途的探究。因此,研发探究新的铁酸镍合成工艺、探索发现更少步骤更加便捷合成铁酸镍高密度氧空位的方法为本论文的设计方案内容。2.具有不同晶面形貌的铁酸镍催化剂的制备及其光热催化性能研究通过不同的合成方法,利用不同的反应溶剂以及模板剂有选择性的制备具有暴露不同晶面的不同形貌的铁酸镍催化剂。探究暴露不同晶面的铁酸镍对催化反应的影响,因为同种元素的化合物由于暴露晶面不同其表面结构会有天壤之别,而且催化剂的暴露晶面直接和反应组分接触,对于催化剂而言,高能活性晶面的暴露量越多对催化剂的催化活性越有利。通过使用导向剂、表面活性剂或调节溶剂PH等方法可以有选择性的合成出有利于催化剂催化活性的高能活性面,并且通过调节其含量使催化剂性能提升更多。因此,研发探究新的铁酸镍合成工艺、探索发现更少步骤更加便捷合成铁酸镍高能活性面的方法为本论文的设计方案内容。3. 3DOM结构铁酸镍催化剂的制备及其光热催化性能研究以不同粒径的PMMA作为硬模板,用镍盐和铁盐溶于一定比例的乙二醇和甲醇溶液作为前驱体,合成不同孔径尺寸的具有三维有序大孔(3DOM)结构的铁酸镍催化剂,探究催化剂的不同孔径尺寸对CO2光热催化反应效率的作用,以及孔径尺寸与催化剂自身比表面积的关系,同时引入光子晶体概念,探究光子效应对CO2光热催化反应性能的影响。3DOM结构的多孔金属氧化物催化剂具有极高的比表面积有助于提高表面催化反应效率,因而成为热点研究领域。而且由于其孔道成周期性排布,因此有可能该催化剂有光子晶体特有的效应---光子禁带(阻止特定波长的光透过,即光在催化剂中停留时间增长),从而通过合成特殊结构达到了提高吸光度的效果,最终同时提高材料的光热催化性能。这使得3DOM金属氧化物催化剂可以进行光催化用途的探究。因此,研发探究新的3DOM铁酸镍合成工艺、探索发现更少步骤更加便捷合成孔径高度规整排列的铁酸镍3DOM结构的方法为本论文的设计方案内容。
[Abstract]:Human activities cause the atmospheric concentration of CO2 is more and more high, the greenhouse effect has caused a serious impact on the environment. So looking for a method to resolve CO2 gas pollution has become a hot topic in the world. Many alternatives, in the condition of CO2 for photothermal catalytic conversion of hydrocarbons into a high feasibility using catalyst, easy to the implementation method. This method can not only reduce the content of CO2 in the atmosphere so as to solve the problem of environmental pollution, and the chemical reaction product is easy to store fuel, can alleviate the current shortage of resources in the world. The ferrite material with low price, simple preparation process, the catalytic reduction of CO2 in the field of research is one of the focuses on the the material. Therefore, this thesis focuses on the optimal performance of nickel ferrite, it was modified by a variety of methods to try to get to the extreme with catalysis New catalytic materials. The detailed research work and achievements of the following three parts: 1. high oxygen vacancy concentration of nickel ferrite catalyst and its catalytic properties of photothermal by solvothermal method, ethylene glycol as the surfactant, the content of oxygen vacancies by adjusting the proportion of ethylene glycol precursor solvents to adjust nickel ferrite catalyst the inner, explore the relationship between concentration and thermal catalytic efficiency of oxygen vacancies in the catalyst, catalytic reaction mechanism of nickel ferrite with oxygen vacancies, and surfactants in the solvothermal synthesis catalyst to catalyst crystal structure. The influence of ability with oxygen vacancy ferrite has high cracking of carbon dioxide and water, there is the preparation process is simple and easy to operate, low price of raw materials and other advantages. But high concentration of oxygen vacancy defects not only as the center, near the valence band created the impurity level, and induce the narrowing of the band gap. This makes To explore the metal oxide catalysts containing oxygen vacancies can be photocatalytic applications. Therefore, research on the new synthetic technology of nickel ferrite, nickel ferrite catalyst exploration discovery method less steps more convenient synthesis of nickel ferrite with high density of oxygen vacancies for the design of.2. with different crystal surface morphology of the system study on Preparation and catalytic performance of photothermal through different synthesis methods, using different reaction solvent and template selective preparation with exposure to Nickel Ferrite Catalysts with different morphologies and different crystal planes. On exposure isomorphous influence surface of nickel ferrite on the catalytic reaction, because of the same element compounds because of different exposure to the surface of crystal surface the structure will have a world of difference, and the catalyst exposed crystal surface directly and reaction components for contact, catalyst, high active crystal surface exposure of more The catalytic activity of the catalyst is more favorable. By using the guide agent, surface active agent or solvent PH method can selectively synthesize a high active surface for catalytic activity, and by adjusting the content of the catalyst performance more. Therefore, research on the new synthetic technology of nickel ferrite, discovery scheme the contents of.3. 3DOM structure of nickel ferrite catalyst less steps more convenient synthesis of nickel ferrite high active surface method for the preparation of catalytic performance and photothermal with different particle size PMMA as hard template, nickel and iron salts dissolved in a certain proportion of ethylene glycol and methanol solution as the precursor, with 3D ordered macroporous synthesis of different pore sizes (3DOM) nickel ferrite catalyst structure, the effect of different pore size of catalyst on CO2 thermal catalytic efficiency, and hole Size and specific surface area of the catalyst itself, at the same time, introducing the concept of photonic crystal, photonic study effect on CO2 thermal catalytic performance on.3DOM structure of porous metal oxide catalyst with high specific surface area is helpful to improve the surface catalytic efficiency, and thus become a hot research field. And because of the periodic arrangement of channels therefore, there may be the catalyst effect, photonic band gap characteristic (to prevent specific wavelengths of light through the light in the catalyst residence time, thus growth) through the synthesis of special structure to improve the absorption effect, thermal catalytic properties of materials and improve the final. This makes 3DOM metal oxide catalysts can be explored photocatalytic applications. Therefore, research on 3DOM nickel ferrite synthesis process of new discovery, fewer steps and more convenient synthetic aperture The highly regular arrangement of nickel ferrite 3DOM structure is the content of the design of this paper.

【学位授予单位】：上海应用技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ138.13;TQ426

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