發(fā)布時間：2018-06-07 06:38

  本文選題：石墨烯 + 熱解��； 參考：《北京化工大學》2011年碩士論文

【摘要】：石墨烯作為碳材料中最年輕的一員,早已引起大家的廣泛關(guān)注。特別是在2010年,Geim因為首次從石墨中剝離出嚴格意義上的石墨烯而獲得諾貝爾化學獎這一殊榮,更是將對其的研究熱潮推向頂峰。 石墨烯是已知世界上最薄的材料,且在力學、熱學、電學、光學等方面都具有優(yōu)異的性能,但是傳統(tǒng)的制備方法并不能大量合成石墨烯,這也阻礙了其在工業(yè)中的應(yīng)用。本文通過研究發(fā)現(xiàn)了一種新型的合成方法一熱解法,可以大量制備出品質(zhì)優(yōu)良的石墨烯,考察了反應(yīng)條件(溫度、配比等)對所得產(chǎn)物的收率、形態(tài)和結(jié)構(gòu)的影響,并對所得樣品進行透射電子顯微鏡(TEM)、掃描電子顯微鏡(SEM)、X射線衍射(XRD)、原子力顯微鏡(AFM)、傅立葉紅外光譜(FIIR)和拉曼光譜測試。同時將其作為鋰離子電池負極材料的進行了電化學性能測試。 研究表明,此方法可以通過熱解二茂鐵和1,2,4-三氯苯混合物直接高收率合成石墨烯,其碳源轉(zhuǎn)化率為42%,在0.5 L釜內(nèi)一次可以合成8g左右。其特點是產(chǎn)量大,遠大于傳統(tǒng)方法所得；片層大(～10 um)而完整,層數(shù)少(3～5層)；結(jié)晶性能較好、缺陷位少。此外,本文通過改變溫度和原料配比,探索出產(chǎn)物石墨烯產(chǎn)量及形貌的變化規(guī)律：(1)隨著反應(yīng)溫度的升高,產(chǎn)物純度以及結(jié)晶度提高,缺陷位減少；(2)隨著炭化處理溫度的升高,石墨烯片層結(jié)晶度提高,層間距先增大后減小,在700℃時最大,產(chǎn)物更傾向于單層石墨烯；(3)尋找出最優(yōu)配比為1：1；當減少1,2,4-三氯苯的含量時,產(chǎn)物產(chǎn)量隨著碳源的減少而下降,且產(chǎn)物形貌變化較明顯,表明氯元素的含量影響了產(chǎn)物的形貌；當減少二茂鐵的含量時,產(chǎn)物產(chǎn)量下降幅度更明顯,但產(chǎn)物形貌無明顯變化,表明催化劑的含量對產(chǎn)物的產(chǎn)量影響更大；(4)由空白樣和對比樣發(fā)現(xiàn),氯元素是影響產(chǎn)物形貌的關(guān)鍵性因素。因此本文最后通過改變含氯碳源,分別得出碳納米管、碳納米帶以及空心納米球等納米材料,并根據(jù)材料形貌隨碳氯原子比的變化推測出石墨烯的合成機理以及氯元素所起的作用。 經(jīng)電化學性能測試得出：該產(chǎn)物在50 mA·g-1電流密度下,首次放電容量為611 mAh·g-1;隨著炭化溫度的升高循環(huán)性能先提高后降低,700℃時達到最優(yōu),30次后可逆循環(huán)容量為413 mAh·g-1。可逆容量的變化主要是因為結(jié)晶度的提高以及層間距的變化影響了鋰離子的嵌脫能力。
[Abstract]:As the youngest member of carbon materials, graphene has attracted much attention. Especially in 2010, the Nobel Prize in Chemistry for the first time to remove graphene from graphite brought its research upsurge to the top. Graphene is the thinnest material in the world and has excellent properties in mechanics, thermodynamics, electricity and optics. However, the traditional preparation method can not synthesize graphene in large quantities, which also hinders its application in industry. In this paper, a new synthetic method, pyrolysis, was found to produce graphene with high quality. The effects of reaction conditions (temperature, ratio, etc.) on the yield, morphology and structure of the products were investigated. The samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FIIR) and Raman spectroscopy. At the same time, the electrochemical performance of the cathode material for lithium ion battery was tested. The results show that this method can be used to synthesize graphene directly in high yield by pyrolysis of ferrocene and 1-trichlorobenzene. The conversion of carbon source is 42 and about 8 g can be synthesized in 0.5 L kettle. It is characterized by its large yield, which is much larger than that obtained by the traditional method, the large and complete lamellar layer (10 umps), the less layers of three layers and five layers, the better crystallization property and the less defect sites. In addition, by changing the temperature and the ratio of raw material, we find out that the change rule of graphene yield and morphology is: 1) with the increase of reaction temperature, the purity and crystallinity of the product increase, the defect position decreases with the increase of carbonization temperature. When the crystallinity of graphene lamellar increases, the interlayer spacing increases first and then decreases, and the maximum at 700 鈩，

本文編號：1990222