CoNC、FeNC催化剂活性中心的探究及其在液相催化氧化、加氢反应中的应用

发布时间：2018-03-11 05:01

本文选题：CoNC/CNT　切入点：CoNC　出处：《华南理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：MeNC催化剂作为一类碳基催化剂,已在电化学催化领域表现出良好的催化活性和稳定性。近来还发现,MeNC催化剂在液相催化反应中也表现出优异的催化活性和稳定性。但到目前为止,对于该类催化剂的活性中心始终没有得到一个准确的认识,这阻碍了高效催化剂的理性设计。本文针对上述问题,采用高温煅烧法合成CoNC/CNT、CoNC、FeNC/CNT催化剂,探究了催化剂的活性中心,并探索了CoNC催化剂在多类液相氧化、加氢反应中的应用。主要研究内容如下:(1)采用邻菲罗啉为含氮配体,通过浸渍和高温热解法合成了CoNC/CNT催化剂,通过XRD、XPS、HRTEM、EELS和毒化实验辨析了该催化剂的活性位。以苯甲醇的氧化酯化反应、硝基苯加氢反应和硝基苯与苯甲醛的加氢偶联反应为探针反应,通过对比盐酸处理前后催化剂的催化性能,发现碳纳米管表面的Co3O4颗粒不是活性位,催化剂真正的活性中心是均匀分散在有缺陷的碳纳米管表面的CoNx,其中N和Co原子比大约为2.2。(2)发展了一种简单、经济的CoNC催化剂合成方法,该方法以氯化铵为氮源、葡萄糖为碳源一锅法水热合成CoNC。对催化剂进行不同程度的酸处理,以苯甲醇的氧化酯化反应为探针反应,发现稀盐酸处理之后催化剂活性最好。对催化剂进行了TEM、STEM、XRD和XPS表征,提出该催化剂活性中心可能是CoNx。该催化剂在芳硝基化合物加氢、醇类选择性氧化等多类有机合成反应中均具有良好的催化性能。(3)采用邻菲罗啉为含氮配体,通过浸渍和高温热解法合成了FeNC/CNT催化剂。以硝基苯加氢反应为探针反应,结合催化性能、毒化实验及催化剂表征结果探究了FeNC/CNT上硝基苯加氢反应活性中心归属,发现FeNC/CNT催化剂对于硝基苯加氢反应的活性中心与Fe、Fe2O3以及FeNx有关,是三者共同的作用。
[Abstract]:MeNC catalyst is a kind of carbon-based catalyst. It has shown good catalytic activity and stability in the field of electrochemical catalysis. Recently, it has also been found that MeNC catalyst also exhibits excellent catalytic activity and stability in liquid-phase catalytic reactions. The active center of this kind of catalyst has not been accurately understood, which hinders the rational design of high efficiency catalyst. In this paper, the active center of the catalyst was investigated by using the high temperature calcination method to synthesize CoNC / CNT / CoNC / CNT catalyst. The application of CoNC catalyst in liquid phase oxidation and hydrogenation reaction was explored. The main research contents are as follows: 1) CoNC/CNT catalyst was synthesized by impregnation and high temperature pyrolysis using o-phenanthroline as nitrogen-containing ligand. The active sites of the catalyst were analyzed by XRDX / XRDP / HRTEMN Eels and toxicity experiments. The oxidation esterification of benzyl alcohol, the hydrogenation of nitrobenzene and the hydrogenation coupling reaction of nitrobenzene with benzaldehyde were used as probe reactions. By comparing the catalytic properties of the catalysts before and after hydrochloric acid treatment, it was found that the Co3O4 particles on the surface of CNTs were not active sites. The real active center of the catalyst is the CoNx, which is uniformly dispersed on the surface of the defective carbon nanotubes, in which the atomic ratio of N and Co is about 2.2.2.) A simple and economical method for the synthesis of CoNC catalyst is developed, which uses ammonium chloride as the nitrogen source. One-pot hydrothermal synthesis of CoNC with glucose as a carbon source was carried out. The catalyst was treated with acid to different degrees, the oxidation esterification of benzyl alcohol was used as probe reaction, and the catalyst activity was found to be the best after the treatment of dilute hydrochloric acid. The catalyst was characterized by TEM-STEM-XRD and XPS. It is suggested that the active center of the catalyst may be CoNx.The catalyst has good catalytic performance in the hydrogenation of aromatic nitro compounds, selective oxidation of alcohols and other organic synthesis reactions. FeNC/CNT catalyst was synthesized by impregnation and pyrolysis at high temperature. The active sites of nitrobenzene hydrogenation on FeNC/CNT were investigated by using nitrobenzene hydrogenation as probe reaction, combined with catalytic performance, toxicization experiment and catalyst characterization. It was found that the active center of FeNC/CNT catalyst for hydrogenation of nitrobenzene was related to Fe _ 2O _ 3 and FeNx.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36

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