本文選題：石墨烯 + 沙林��； 參考：《長春大學》2017年碩士論文

【摘要】：近年來,曾在戰(zhàn)爭及恐怖襲擊中被廣泛使用的化學毒劑對人類及國家安全造成了極大傷害,因此,如何有效消除這一化學毒劑成為科研工作者和國家安全面臨的主要挑戰(zhàn)。有效消除化學毒劑一個行之有效的辦法就是選擇合適的吸附材料。石墨烯具有超高的比表面積、良好的熱學和化學穩(wěn)定性、易于合成、成本低,而生產(chǎn)中形成的缺陷、雜質(zhì)、化學官能團又可能會創(chuàng)造更多的吸附活性位置從而有效提高其吸附活性,因此,成為極具前景的吸附材料。眾所周知,理想石墨烯對原子或分子的吸附為弱的物理吸附,要想實現(xiàn)石墨烯基納米材料優(yōu)異的吸附性能,必須對理想石墨烯進行改性,提高其吸附活性。同傳統(tǒng)的貴金屬相比,鐵(Fe)原料豐富,成本低,環(huán)境友好,反應(yīng)效率高。因而我們選擇過渡金屬Fe及其團簇對本征石墨烯進行修飾,進而將其作為中間媒介去吸附沙林分子。從理論上模擬Fe改性石墨烯對沙林氣體的吸附作用,通過計算各種吸附情況下的相關(guān)性質(zhì),揭示其吸附機制。有利于明確和理解沙林分子的識別、清除、防護、從有毒向無毒轉(zhuǎn)化等問題,并將為制備安全、有效的化學毒劑防護系統(tǒng)提供理論依據(jù)。本文通過基于密度泛函理論的第一性原理計算方法,系統(tǒng)研究了本征石墨烯吸附沙林分子、Fe及其二元團簇改性石墨烯吸附沙林分子以及石墨烯對三元及四元Fe團簇的吸附性質(zhì)。計算了體系吸附能、電子態(tài)密度和密立根電荷密度等相關(guān)性質(zhì)。通過對比分析我們的計算結(jié)果可知,本征石墨烯對沙林的吸附作用為弱的物理吸附;Fe原子的引入,明顯增強了石墨烯基底對沙林的吸附作用,沙林分子與Fe改性石墨烯體系之間存在明顯的電荷轉(zhuǎn)移;同單個Fe原子改性石墨烯相比,二元Fe團簇改性石墨烯對沙林分子的吸附能明顯增大,導致沙林分子態(tài)密度更加彌散,并且向低能方面移動,沙林分子與石墨烯基底之間的電荷轉(zhuǎn)移增多;Fe原子團簇與本征石墨烯的相互作用強烈依賴于團簇的形狀和尺寸,三元Fe團簇易于以三角形平面垂直于石墨烯表面進行吸附,而四元Fe團簇易于以四面體形狀吸附在石墨烯表面。即:隨著Fe原子個數(shù)增加,體系吸附能增大,Fe團簇與石墨烯基底之間的電荷轉(zhuǎn)移增強,吸附作用增強。
[Abstract]:In recent years, chemical agents which have been widely used in war and terrorist attacks have caused great harm to human and national security. Therefore, how to effectively eliminate this chemical agent has become a major challenge for researchers and national security. One effective way to eliminate chemical agents is to select suitable adsorption materials. Graphene has a high specific surface area, good thermal and chemical stability, easy synthesis, low cost, while the production of defects, impurities, Chemical functional groups may also create more sites of adsorption activity to effectively improve their adsorption activity, therefore, become a very promising adsorption materials. It is well known that the adsorption of ideal graphene to atoms or molecules is weak physical adsorption. In order to achieve excellent adsorption performance of graphene based nanomaterials, it is necessary to modify ideal graphene to improve its adsorption activity. Compared with the traditional precious metals, iron (Fe) is rich in raw materials, low in cost, environmentally friendly and high in reaction efficiency. Therefore, the transition metal Fe and its clusters were chosen to modify the intrinsic graphene, which was then used as an intermediate to adsorb sarin molecules. The adsorption mechanism of Fe modified graphene on sarin gas was studied by calculating the related properties of various adsorption conditions. It is helpful to clear and understand the identification, removal, protection and conversion from toxic to non-toxic of sarin molecules, and will provide theoretical basis for the preparation of safe and effective chemical agent protection system. Based on the density functional theory (DFT), the adsorption properties of ternary and quaternary Fe clusters by graphene adsorbed on sarin and its binary cluster modified graphene are studied systematically in this paper. The adsorption energy, electron density of state and Millikan charge density were calculated. By comparing and analyzing our calculation results, it can be seen that the adsorption of sarin by intrinsic graphene is a weak physical adsorption of Fe atoms, which obviously enhances the adsorption of sarin on graphene substrate. Compared with the single Fe atom modified graphene, the adsorption energy of the binary Fe cluster modified graphene on the sarin molecule is obviously increased, which leads to the diffusion of the density of states of the sarin molecule. The charge transfer between the sarin molecule and the graphene substrate increases and the interaction between the Fe cluster and the intrinsic graphene is strongly dependent on the shape and size of the cluster. Ternary Fe clusters are easily adsorbed on graphene surface in triangular plane, while quaternary Fe clusters are easily adsorbed on graphene surface in the shape of tetrahedron. That is, with the increase of the number of Fe atoms, the adsorption energy of the system increases with the increase of the charge transfer between the Fe cluster and the graphene substrate, and the adsorption effect is enhanced.
【學位授予單位】：長春大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O647.3

【參考文獻】

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1 廖文裕;蘇亞欣;周v，

本文編號：2072208