沥青质基多孔炭在掺氮过程中元素的演变规律

发布时间：2018-02-26 00:11

  本文关键词： 沥青质 预氧化 氮掺杂 物理活化 超级电容器　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：氮掺杂多孔炭材料由于具有独特机械、光学、电子等特性使得其在储能、催化、分离等领域中显示出诱人的应用前景。研究热处理制备过程中掺氮炭材料的结构、组成及表面化学性质的变化特点,对于实现炭材料定向掺氮具有重要意义。本文主要以煤液化残渣基沥青质为碳源,MS为氮源,制备氮掺杂炭材料,主要研究成炭热处理过程中氮掺杂炭材料表面官能团的变化；在此基础上通过CO2活化法制备了氮掺杂的多孔炭材料,并测试了掺氮多孔炭材料的电化学性能。主要研究内容和成果如下：(1)热处理过程中氮掺杂炭材料表面官能团的变化研究沥青质(A)经预氧化得到预氧化的沥青质(AO),将预氧化后的沥青质(AO)与氮源(MS)混合放入管式炉中,在不同温度、氮气环境下进行热处理制备氮掺杂炭材料(AOM-Ts),主要研究热处理温度变化过程中氮掺杂炭材料表面官能团的演变规律。结果表明：相比于A,AO在热处理过程中表现出较好的热稳定性,在热处理温度为800℃时其炭化收率高达63.75%；经处理的AO出现了明显的羰基官能团,所含氧元素含量明显高于A,这些含氧官能团的存在为MS中的-NH2反应提供了丰富的活性位；热处理温度在500℃以上时,在相同的热处理温度下,AOM-T的氮元素、氧元素的含量高于AM-T；对于样品AOM-Ts而言,热处理温度在500℃之前,含氮官能团主要以N-5和N-6两种形式存在；热处理温度为600℃时,含氮官能团出现了N-Q,700℃时出现了N-X；随着热处理温度的升高,N-5的含量基本上保持不变,N-6的含量逐渐降低,而N-X和N-Q的含量均增加；热处理温度的变化对含氧官能团存在的形态没有明显的影响,均以O-Ⅰ和O-Ⅱ类型存在,且O-Ⅱ的含量大于O-Ⅰ的含量。(2)沥青质氧化前后对掺氮炭材料表面组成、结构以及电化学性能的影响分别以沥青质/预氧化的煤液化残渣沥青质为原料、MS为氮源,采用CO2物理活法制备氮掺杂的多孔炭材料,研究沥青质预氧化处理工艺对其掺氮造孔后的组成、结构以及电化学性能的影响。结果表明：预氧化后的样品中所含的氮元素含量、N-5和N-6总含量、比表面积和孔容均明显变大,其含氮量为4.85 wt.%,比表高达986 m2.g-1,孔容为0.61cm3.g-1；在三电极体系下,6 M KOH电解液中100 mA·g-1的电流密度下,预氧化处理后的样品具有最大的质量比电容,其值为197 F·g-1；当电流密度达到10 A·g-1时,其质量比电容仍可达到136 F·g-1；在两电极体系、1 A·g-1的电流密度下,经过5000次循环充放电,其电容值的保持率在90%以上,表现出良好的充放电循环性能。
[Abstract]:Nitrogen doped porous carbon materials have shown attractive applications in the fields of energy storage, catalysis and separation due to their unique mechanical, optical and electronic properties. The change of composition and surface chemical properties is of great significance to realize the directional nitrogen doping of carbon materials. In this paper, nitrogen doped carbon materials are prepared by using coal liquefaction residue based asphaltene as carbon source and MS as nitrogen source. The changes of functional groups on the surface of nitrogen-doped carbon materials during heat treatment were studied, and the nitrogen-doped porous carbon materials were prepared by CO2 activation method. The electrochemical properties of nitrogen-doped porous carbon materials were tested. The main research contents and results are as follows: 1) the changes of functional groups on the surface of nitrogen doped carbon materials during heat treatment; The pre-oxidized asphaltene (AO) and nitrogen source (MSS) are mixed into a tube furnace. At different temperatures, Nitrogen doped carbon materials were prepared by heat treatment in nitrogen atmosphere. The evolution of surface functional groups of nitrogen doped carbon materials during heat treatment temperature change was studied. The results showed that compared with AAO, the surface functional groups of nitrogen doped carbon materials showed better thermal stability during heat treatment. The carbonization yield is up to 63.75 at the heat treatment temperature of 800 鈩，

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