本文選題：碳納米管 + 吸附　； 參考：《中國海洋大學》2014年博士論文

【摘要】：納米材料領(lǐng)域的研究熱點——碳納米管，因其特有的一維幾何結(jié)構(gòu)，具有獨特的物理化學性能，其對金屬的吸附在能源和水資源等領(lǐng)域具有廣闊的應(yīng)用前景，吸引了很多研究者的關(guān)注。本論文運用第一性原理計算方法研究了碳納米管對堿土金屬原子、堿金屬氯化物及堿土金屬氯化物的吸附特性，分析了吸附的機理，得到了如下主要結(jié)果： 1．碳納米管對堿土金屬原子的吸附。碳納米管對堿土金屬原子的吸附主要依賴于碳納米管的手性、位置以及堿土金屬的特性。完整蓋帽的(9,0)碳納米管對堿土金屬的吸附能大于完整蓋帽的(5,5)碳納米管對堿土金屬的吸附能。堿土金屬原子在碳納米管五元環(huán)和六元環(huán)兩個位置處的吸附存在明顯的不同，堿土金屬原子在六元環(huán)上的吸附能明顯大于在五元環(huán)上的數(shù)值，并與碳納米管的手性無關(guān)。碳納米管吸附堿土金屬原子后功函數(shù)明顯降低，并與被吸附堿土金屬原子的電負性成線性關(guān)系。堿土金屬原子的電負性越大，吸附后碳納米管功函數(shù)降低的越小。碳納米管的功函數(shù)可以通過其吸附不同金屬原子來進行調(diào)控。 2．碳納米管對堿土金屬氯化物、堿金屬氯化物的吸附。碳納米管對堿土金屬氯化物、堿金屬氯化物的吸附能小于600meV，屬于物理吸附。吸附能大小主要與氯化物的電偶極矩、吸附距離兩個參量有關(guān)，同族金屬氯化物的吸附能和偶極矩與吸附距離的平方之比成線性關(guān)系。利用差分電荷密度、態(tài)密度和Bader電荷分析了碳納米管與金屬氯化物間的吸附機理，兩者之間并沒有發(fā)生電荷的轉(zhuǎn)移，，吸附主要是通過偶極相互作用來完成的。 3．水分子對碳納米管吸附金屬氯化物的影響。碳納米管基本不吸附水分子，因此在氯化物與水分子共存的環(huán)境中，碳納米管將優(yōu)先吸附氯化物；吸附了金屬氯化物的碳納米管對水分子的吸附能明顯增大，說明金屬氯化物修飾后的碳納米管與水分子相互作用增強。這一結(jié)果對碳納米管應(yīng)用于海水資源提取提供了理論依據(jù)。
[Abstract]:Carbon nanotubes (CNTs), a research hotspot in the field of nanomaterials, have unique physical and chemical properties because of their unique one-dimensional geometry. The adsorption of metals on carbon nanotubes has a broad application prospect in the fields of energy and water resources. It has attracted the attention of many researchers. In this paper, the adsorption characteristics of alkali earth metal atom, alkali metal chloride and alkali earth metal chloride were studied by first principle calculation method. The adsorption mechanism was analyzed and the main results were obtained as follows: 1. Adsorption of alkali earth metal atoms by carbon nanotubes. The adsorption of alkali earth metal atoms by carbon nanotubes mainly depends on the chirality, location and characteristics of alkali earth metals. The adsorption energy of carbon nanotubes to alkaline earth metals is higher than that of complete capped carbon nanotubes to alkaline earth metals. The adsorption energy of alkali earth metal atom on the six-member ring is higher than that on the five-member ring, and it is independent of the chirality of carbon nanotube. The work function of carbon nanotubes after adsorption of alkali earth metal atoms decreases obviously and is linearly related to the electronegativity of the adsorbed alkali earth metal atoms. The larger the electronegativity of alkali earth metal atoms, the smaller the work function of carbon nanotubes after adsorption. The work function of carbon nanotubes can be regulated by their adsorption of different metal atoms. 2. Adsorption of Alkali Earth Metal Chloride and Alkali Metal Chloride by carbon Nanotubes. The adsorption energy of alkali earth metal chloride and alkali metal chloride by carbon nanotubes is less than 600meV, so it belongs to physical adsorption. The adsorption energy is mainly related to the electric dipole moment and the adsorption distance of chloride, and the adsorption energy and the ratio of dipole moment to square of adsorption distance are linear. The adsorption mechanism between carbon nanotubes and metal chloride was analyzed by differential charge density, density of states and Bader charge. There was no charge transfer between them. The adsorption was mainly accomplished by dipole interaction. 3. Effects of Water molecules on adsorption of Metal Chloride by carbon Nanotubes. Carbon nanotubes do not adsorb water molecules, so carbon nanotubes will preferentially adsorb chlorides in the presence of chloride and water molecules, and carbon nanotubes that adsorb metal chlorides have a significantly higher adsorption energy for water molecules. The results show that the interaction between carbon nanotubes modified by metal chloride and water molecules is enhanced. This result provides a theoretical basis for the application of Yu Hai in the extraction of water resources in carbon nanotubes (CNTs).
【學位授予單位】：中國海洋大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：P746

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