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First-principles Calculation of Li Atom Adsorbing on Carbon Nanotubes

Author: LiLiangGuo
Tutor: YuanGuang
School: Ocean University of China
Course: Optical Engineering
Keywords: First-principle Carbon nanotubes Electronic structure Adsorption
CLC: TB383.1
Type: Master's thesis
Year: 2009
Downloads: 341
Quote: 1
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Abstract

The carbon nanotubes have rapidly attracted a lot of attention in the domain of material science because of their unique physical,chemical and structure properties,as well as their signification potential on a broad range of applications.Hence,carbon nanotubes have become one of representative and typical nanomaterials.However,when carbon nanotubes have been doped,substituted and decorated,the presence of defects and impurities can give rise to nanotube functionalization and enhance range of applications.The purpose of this thesis is to work through the first principles of quantum mechanics based on the theoretical calculation to study the oxygen-doped carbon nanotubes before and after the adsorption properties of lithium and lithium adsorption on carbon nanotubes caused by the nature of the effects of different carbon nanotubes for further study of alkali metal adsorption selectivity,adsorption capacity and adsorption,as well as the location of different alkali metal ions of different lay the foundation for the impact of carbon nanotubes.The results of simulation experiments to guide the design of new materials and has an important significance.The thesis is organized as followsFirstly,the basic knowledge of carbon nanotubes are introduced,which includes its discovery,structure,classification,properties,applications and preparation methods.The study of lithium adsorption progress are introduced.The research methods,the purpose and significance are briefly discussed.In chapterⅡ,the first-principle and the software PWSCF which are based on the Density Function Theory(DFT) are introduced in details.A wide variety of computing software is also introduced.In ChapterⅢ,the nature of the electronic structure changes of(3,3) carbon nanotubes before or after the adsorption of lithium is calculated and discussed.In this thesis,exchange-related to the amendment is adopted PBE functionals.Select(3,3) single-walled carbon nanotubes,a total of two cycles of 24 atoms,the initial value of bond length 1.42(?),each cycle of long carbon nanotubes 2.45951225(?),in the calculation of the process to select the vacuum level is greater than 10(?).Used in calculating the six k-point sampling tube axis to One-dimensional Brillouin zone,that is,K-point grid for the 1×1×6,mmcated Notoro 408 eV,the convergence conditions of our 0.05 eV/(?),the energy convergence conditions of 0.005 eV.softwares of the ORIGIN or the MATLAB are used for drawing graphics.The results of the adsorption energy,density of states and band structure calculated indicate that the adsorption of carbon nanotubes outside tube for lithium adsorption than the adsorption of lithium inside tube is more likely appear.In ChapterⅣ,the nature of the electronic structure changes of the calculation and a mix of one oxygen atom of the carbon nanotubes before or after the adsorption of lithium are calculated and discussed.Calculation using 12 k points to a sample tube axis to One-dimensional Brillouin zone,that is,k-point grid for the 1×1×12,truncated Notoro 400 eV,the convergence conditions of our 0.02 eV/(?),the energy convergence conditions of 0.002 eV.The results of the adsorption energy,density of states and band structure calculated indicate that lithium adsorption is more easily after one oxygen atom doping the carbon nanotube,and larger changes of the electronic structure have taken place.The adsorption of carbon nanotubes outside tube for lithium adsorption than the adsorption of carbon nanotubes inside tube for lithium adsorption is more likely appear.In summary,a final conclusion is drawn for all the results obtained.

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