發(fā)布時(shí)間：2018-05-07 08:31

  本文選題：雜原子摻雜 + 石墨烯氣凝膠�。� 參考：《長春理工大學(xué)》2016年碩士論文

【摘要】：具有低的實(shí)際操作溫度、對環(huán)境零污染、高的能量密度和較長的壽命等特點(diǎn),使得直接甲醇燃料電池(DMFCs)得到廣泛關(guān)注。然而,DMFCs陰極動力學(xué)反應(yīng)速率很慢,從而影響了DMFCs的實(shí)際應(yīng)用。迄今為止,鉑系催化劑具有一些優(yōu)良的性質(zhì)(如較低的過電位、高的電流密度等),因而應(yīng)用范圍廣泛。但是,鉑系催化劑也存在許多缺點(diǎn),例如價(jià)格昂貴、有一定的毒性、不穩(wěn)定等,這些缺陷在不同程度上都影響了直接甲醇燃料電池的更廣泛的應(yīng)用。近些年來,在氧還原反應(yīng)(ORR)中,雜原子摻雜的碳材料是一類具有高催化活性的催化劑。本文采用溶劑熱和高溫?zé)崽幚淼姆椒ǚ謩e制備了三種石墨烯氣凝膠:首先,5-氨基-1,3,4-噻重氮-2-硫醇(C2H3N3S2)作為硫源與氮源,與氧化石墨(GO)進(jìn)行水熱反應(yīng),形成的聚5-氨基-1,3,4-噻重氮-2-硫醇修飾的石墨烯水凝膠,再經(jīng)過冷凍干燥得到聚5-氨基-1,3,4-噻重氮-2-硫醇修飾的石墨烯氣凝膠,經(jīng)過高溫煅燒得到氮硫共摻雜的石墨烯氣凝膠(N-S-GAs);其次,用2,6-二氨基吡啶作為氮源通過與GO進(jìn)行水熱反應(yīng),然后對形成的水凝膠進(jìn)行冷凍干燥和高溫煅燒得到氮摻雜的氣凝膠,制備了單獨(dú)氮摻雜石墨烯氣凝膠(N-GAs);最后,為了改善N-GAs的性能,通過原位的方法在第二個體系中引入鐵離子,對一定比例的2,6-二氨基吡啶、硝酸鐵(Fe(NO3)3)和GO的混合溶液進(jìn)行水熱反應(yīng),然后經(jīng)過冷凍干燥和高溫煅燒后得到鐵氮雙摻的石墨烯氣凝膠(Fe-N-GAs)。經(jīng)過高溫煅燒后,鐵離子轉(zhuǎn)變成碳化鐵納米粒子,并研究金屬加入量對催化性能的影響,并研究了其在酸性條件下的催化性能。分別對所形成的三種催化劑進(jìn)行了結(jié)構(gòu)表征和電化學(xué)測試的表征,例如采用掃描電子顯微技術(shù)(SEM)和透射電子顯微技術(shù)(TEM)對所制備的復(fù)合物的形貌進(jìn)行表征。使用氮吸附脫附等溫線、拉曼光譜分析和X射線光電子能譜技術(shù)對材料的孔結(jié)構(gòu)和結(jié)構(gòu)進(jìn)行分析。采用旋轉(zhuǎn)圓盤電極實(shí)驗(yàn)(RDE)和旋轉(zhuǎn)環(huán)盤電極實(shí)驗(yàn)(RRDE)對所制備的催化劑在堿性介質(zhì)中對氧氣還原的催化活性。測試結(jié)果表明所制備的催化劑有很好的催化性能,如較正的起峰電位、較大的極限電流密度以及好的耐甲醇性能和穩(wěn)定性等。因此,在堿性介質(zhì)中雜原子摻雜的石墨烯氣凝膠是一類有前景的陰極氧氣還原催化劑。
[Abstract]:With the characteristics of low operating temperature, zero pollution to environment, high energy density and long life, DMFCsof direct methanol fuel cell (DMFCs) have been paid more and more attention. However, the cathodic kinetic reaction rate of DMFCs is very slow, which affects the practical application of DMFCs. So far, the platinum catalyst has some excellent properties (such as low overpotential, high current density and so on), so it is widely used. However, platinum catalysts also have many disadvantages, such as high price, toxicity, instability and so on. These defects affect the wider application of direct methanol fuel cells in varying degrees. In recent years, hetero-atom doped carbon is a kind of catalyst with high catalytic activity in oxygen reduction reaction (ORR). In this paper, three kinds of graphene aerogels were prepared by solvothermal and high temperature heat treatment. Firstly, 5-amino-1-aniline 4-thiazo-4-thiazo-2-mercaptan (C2H3N3S2) was used as sulfur and nitrogen source, and hydrothermal reaction with graphite oxide (GOO) was carried out. The graphene hydrogel modified by poly5-amino-1-thiazo-4-thiazo-2-mercaptan was prepared by freeze-drying, and then the graphene aerogel modified by poly5-amino-1-diazo-3-thiazo-4-thio-2-mercaptan was obtained by freeze-drying. After high temperature calcinations, N-S-GAs-doped graphene aerogels were prepared. Secondly, N-doped aerogels were prepared by freeze-drying and calcining of N-doped aerogels by hydrothermal reaction with go with 2O6-diaminopyridine as nitrogen source, then the resulting hydrogels were freeze-dried and calcined at high temperature to obtain nitrogen-doped aerogels. In order to improve the properties of N-GAs, iron ions were introduced into the second system by in situ method. The mixed solution of ferric nitrate Fegno _ 3) and go was hydrothermal reacted, and then freeze-dried and calcined at high temperature to obtain Fe-N-GAsN aerogel mixed with iron and nitrogen. After high temperature calcination, iron ions were transformed into iron carbide nanoparticles, and the effect of metal addition on the catalytic performance was studied. The catalytic properties of iron ions in acidic conditions were also studied. The structure and electrochemical properties of the three catalysts were characterized, such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to characterize the morphology of the composites. Nitrogen adsorption and desorption isotherms, Raman spectroscopy and X-ray photoelectron spectroscopy were used to analyze the pore structure and structure of the materials. The catalytic activity of the prepared catalyst for oxygen reduction in alkaline medium was studied by rotating disk electrode (RDE) and rotating ring disk electrode (RRDE). The results show that the prepared catalysts have good catalytic performance, such as positive peak starting potential, high limit current density, good methanol resistance and stability. Therefore, graphene aerogels doped with heteroatoms in alkaline media are a promising cathodic oxygen reduction catalyst.
【學(xué)位授予單位】：長春理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：O643.36
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本文編號：1856198