本文選題：三維石墨烯納米復(fù)合材料　切入點(diǎn)：氧化石墨烯　出處：《河北大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：石墨烯是一種通過碳原子sp2雜化形成的六邊形蜂窩狀結(jié)構(gòu)二維原子晶體,其特殊的二維結(jié)構(gòu),致使其在導(dǎo)電性,導(dǎo)熱性等諸多方面具有非常優(yōu)異的性能。但是,二維材料在一定程度上限制了石墨烯在應(yīng)用方面的拓展。石墨烯與溶劑間的作用比較弱,且二維的強(qiáng)共軛結(jié)構(gòu)使層與層之間的范德華力很強(qiáng),形成間距為0.34 nm的結(jié)合體,所以石墨烯很容易堆積卻難以剝離分散,這對(duì)石墨烯功能材料的進(jìn)一步加工制備和應(yīng)用帶來了很大的困難。采用化學(xué)氧化石墨粉制備的氧化石墨烯,不僅容易分散在多種溶劑里,還可以通過還原轉(zhuǎn)化為石墨烯,因此是迄今為止研究最廣泛的石墨烯衍生物。與石墨類似,氧化石墨同樣保持著層狀結(jié)構(gòu),不同的是,石墨片層經(jīng)強(qiáng)酸性以及強(qiáng)氧化性的溶劑氧化后,引入了許多不同的含氧官能團(tuán),如羥基、環(huán)氧基、羰基和羧基等,經(jīng)過剝離得到的單片層的結(jié)構(gòu),即氧化石墨烯。而且因?yàn)閷訝罱Y(jié)構(gòu)易于分散到溶劑中,孔結(jié)構(gòu)得到了很好的保護(hù)。利用氧化石墨烯的獨(dú)特性質(zhì),將二維材料組裝為三維石墨烯納米復(fù)合材料,可以很好的解決二維材料在應(yīng)用上的困難,對(duì)于石墨烯的基礎(chǔ)和應(yīng)用研究具有重大意義。因此本文主要針對(duì)其含氧官能團(tuán)和孔結(jié)構(gòu)等特性,研究了多種三維多孔石墨烯納米復(fù)合材料。本文的內(nèi)容和成果如下:1.以氧化石墨烯為主要原料,利用氧化石墨烯層間的含氧官能團(tuán)與不同硼酸衍生物反應(yīng),成功制備了三種不同的插層結(jié)構(gòu),即氧化石墨烯骨架結(jié)構(gòu)材料(GOFs),并對(duì)對(duì)羧基苯硼酸做連接劑的GOF進(jìn)行了鋰摻雜。利用掃描電子顯微鏡(SEM),X射線衍射(XRD),氮?dú)馕綔y(cè)試以及熱重分析(TGA)等手段對(duì)材料的不同結(jié)鉤進(jìn)行了分析,并采用電化學(xué)分析的方法分析了其在氧還原反應(yīng)(ORR)的催化的活性和電子轉(zhuǎn)移歷程。結(jié)構(gòu)表征表明,制備的GOFs的形貌顯示出明顯的層狀結(jié)構(gòu),層間距提高了0.45?,TGA結(jié)果表明熱穩(wěn)定性增強(qiáng),比表面積顯著提高,說明氧化石墨烯插層結(jié)構(gòu)被成功制備。性能分析表明GOFs可用于催化雙氧水的電化學(xué)合成,且具有選擇性高、綠色環(huán)保、成本較低等優(yōu)勢(shì)。2.以氧化石墨烯為原料,通過水熱反應(yīng),制備了自組裝石墨烯,并以此為基礎(chǔ),通過有機(jī)溶液置換、直接冷凍干燥以及PECVD生長等多種手段,制備了多種三維石墨烯復(fù)合材料,主要包括:氧化石墨烯直接自組裝得到的水凝膠,有機(jī)溶劑置換并凍干后得到的三維石墨烯氣凝膠,PECVD生長的石墨烯納米墻和氧化石墨烯復(fù)合自組裝,以三維石墨烯氣凝膠為基底生長石墨烯納米墻復(fù)合材料。通過一系列表征手段,分析了其結(jié)構(gòu)與性能特點(diǎn)。通過改良設(shè)計(jì)路線得到了三維石墨烯氣凝膠以及它與石墨烯納米墻的復(fù)合材料,具有疏松規(guī)整的三維孔結(jié)構(gòu),比表面積提高到了795 m2/g,提高了近兩倍。三維石墨烯氣凝膠的氫氣存儲(chǔ)質(zhì)量密度高達(dá)5.5%。
[Abstract]:Graphene is a hexagonal honeycomb two-dimensional atomic crystal formed by carbon atom sp2 hybrid. Its special two-dimensional structure makes it have excellent properties in many aspects, such as electrical conductivity, thermal conductivity and so on. To some extent, the application of graphene is limited by two-dimensional materials. The interaction between graphene and solvent is weak, and the strong conjugate structure of two dimensional makes the van der Waals force between layers very strong, forming a bond with a distance of 0.34 nm. Therefore, graphene is easy to pile up but difficult to peel and disperse, which brings great difficulties to the further processing and application of graphene functional materials. Not only are they easily dispersed in a variety of solvents, but they can also be reduced to graphene, so they are by far the most widely studied derivatives of graphene. Similar to graphite, graphite oxide also maintains a layered structure. After strongly acidic and strongly oxidized solvents, the graphite lamellae has introduced many different oxygen-containing functional groups, such as hydroxyl, epoxy, carbonyl and carboxyl, etc. That is graphene oxide. And because the layered structure is easily dispersed into the solvent, the pore structure is well protected. Using the unique properties of graphene oxide, the two-dimensional materials are assembled into three-dimensional graphene nanocomposites. It can solve the difficulties in the application of two-dimensional materials and has great significance for the basic and applied research of graphene. Therefore, this paper mainly focuses on the properties of oxygen functional groups and pore structures. A variety of three-dimensional porous graphene nanocomposites have been studied. The main contents and results of this paper are as follows: 1. Using graphene oxide as the main raw material, the oxygen-containing functional groups between graphene oxide layers are used to react with different boric acid derivatives. Three different intercalation structures have been successfully prepared. The framework structure of graphene oxide (GFA) was obtained by adding lithium to the GOF, which was used as the bonding agent for p-carboxyphenylboric acid. The GOF was not prepared by means of scanning electron microscope (SEM), X-ray diffraction (XRD), nitrogen adsorption test and thermogravimetric analysis (TGA). The same knot hook was analyzed. The catalytic activity and electron transfer mechanism of the prepared GOFs in oxygen reduction reaction orr were analyzed by electrochemical analysis. The structure characterization showed that the morphology of the prepared GOFs showed obvious layered structure, and the interlayer spacing was increased by 0.45? The results showed that the thermal stability was enhanced and the specific surface area was significantly improved, which indicated that the graphene oxide intercalation structure was successfully prepared. The performance analysis showed that GOFs could be used to catalyze the electrochemical synthesis of hydrogen peroxide with high selectivity and environmental protection. 2. Using graphene oxide as raw material, self-assembled graphene was prepared by hydrothermal reaction. On the basis of this, various methods such as replacement of organic solution, direct freeze-drying and PECVD growth were used. A variety of three dimensional graphene composites were prepared, including hydrogels prepared by direct self-assembly of graphene oxide. Three dimensional graphene aerogels grown by PECVD were prepared by replacing and freeze-drying with organic solvents. The composite self-assembly of graphene nanowall and graphene oxide was carried out. Three dimensional graphene aerogel was used as substrate to grow graphene nanowall composites. The structure and properties were analyzed. Through the improved design route, the three-dimensional graphene aerogel and its composites with graphene nanowall were obtained. The specific surface area was increased to 795 m2 / g, nearly twice as much. The hydrogen storage mass density of three dimensional graphene aerogels was up to 5.5%.
【學(xué)位授予單位】：河北大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ127.11;TB33

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本文編號(hào)：1625847