The Intrinsic Features And Analysis Of The Non-covalent Interaction On Surface Of Series Carbon-based Solids

Carbon-based solids with unique structures enrich their physicochemical properties and show great application prospects in the fields of energy,catalysis,chemical separation and biometrics.However,there are still great challenges in exploring the mechanism of surface interactions between different molecules and solid carbon-based materials.It is very important for the wide application of carbon-based solids to make clear the interfacial laws and control methods through systematic study.Based on density functional theory,high-precision ab initio calculation and large-scale molecular dynamics simulation,the paper mainly studies the surface behavior of different carbon-based solids,including coal,fullerenes,graphene and graphdiyne.The main work includes the surface behavior of water on lignite molecules,the endohedral of single atom Li/Li+ and ten-electron atom/molecule system in a series of fullerene nanometer carbon cage,the adsorption of nucleobases on the surface of graphene/graphdiyne nanoflake,etc.In this paper,the geometric characteristics of the stable adsorption of different molecules on the surface of these carbon-based solids are described.Based on the energy decomposition(EDA)method,the interactions between the composite system fragments are decomposed into four different physical components.Based on reduced density gradient(RDG)analysis,difference density of electron density,orbital hybridization,charge transfer and other methods,the physical nature of interaction is further explored.This paper provides a new idea for further exploring the mechanism and assembly law of non-covalent interaction on the surface of carbon-based solid.The main contents are as follows:(1)This study is based on the first principles and molecular dynamics method to study the nature of the interaction between coal molecules and water.In density functional theory,the model of water molecules adsorbed on the different functional groups in lignite was constructed by using genmer tool.The independent gradient model(IGM)shows that the van der Waals and hydrogen bond interaction is the main interaction between the two monomers.In order to fully express the hydrogen bond and van der Waals on the stability of the composite system and monomer bonding,the stability of the monomer is investigated from the perspective of energy.The results show that the reaction energy is an important part of the adsorption process between lignite and water.And because of the hydrogen bond Eeistat is the main form of action of the composite system.In the molecular dynamics simulation,the effect nature of different lignite molecular number in water solvent was investigated.After the simulation of molecular dynamics,a certain agglomeration will occur.With the increase of the system,the increase of each item in the bonding interaction is proportional to the increase of the number of coal molecules.Except for the interaction between with the number of 10 lignite molecules and water,the intermolecular(water and coal)is mainly presented in the form of long-range dispersion correction.In the 10 lignite molecules systems,it is mainly presented in the form of electrostatic interaction.The resulting energy,potential energy,solvent accessible surface area and number of hydrogen bonds are proportional to the number of coal molecules,respectively.(2)Based on density functional theory,this study investigated the encapsulation behavior of Li atoms and Li+of fullerenes(Cn=20?60 and 70)of different sizes.After the structure was fully optimized and the binding energy(Eb),deformation energy(Edef)and reaction energy(Eint)of the system were calculated,it was found that fullerenes were beneficial to the encapsulation of Li and Li+,and Eint played a major role in the adsorption process.The encapsulation of Li+is not as energetic as that of Li.The non-central position of Li and Li+is more advantageous than the central position.In the structure of energy decomposition,electrostatic interaction is more important to the stabilization of Li+@Cn than Li@Cn.The exchange repulsion interaction of Li+@Cn is greater than that of Li@Cn,and the dispersion interaction is not important to the interaction between Li or Li+and carbon cage.(3)The encapsulation behavior of fullerene C60 was studied by selecting the famous ten-electron atom or cluster classical system.Based on the first principle,the energy and energy decomposition of the internal packaging system are calculated.The contributions to the main attraction of the neutral,cationic,and anion X10e@C60 systems are different.The interaction between neutral and C60 cage is mainly the dispersion interaction.For the cationic X10e@C60 system,the main form of interaction is orbital interaction,and electrostatic interaction is the most important part of the interaction between anion endofullerene fragments.(4)Using the first-principle DFT calculation method,the interactions between the four novel NBs and graphene nanoflake substrates were studied,namely,5-mC,5-hmC,5-fC and 5-caC.The structure,binding energy and interaction properties of the new NBs are calculated in detail and compared with the original NBs.And the ording is 5-fC<5-hmC<5-mC<5-caC<C.Four new compounds of NBs Eb is strong negative,?EPauli(?)is positive,?Eelstar(?),?Eorb(?)??Edisp(?)are negative.And ?Edisp(?)are the main form.(5)The first principle was used to explore the interaction mechanism between nucleobases and graphene GR(C114H30)and graphdiyne GDY(C90H18)solid materials,and the energy and energy decomposition of each complex system were calculated respectively.From the perspective of energy,Eb is negative regardless of GR or GDY.But GR/NBs has a more negative Eb,and GR/NBs has a higher Eint.From the results of the EDA found that ?Edisp(?)are the main effect of different substrate.The weak interaction is the main form of the two fragments.