Investigations Of The Interactions Between Atoms/Molecules And Graphene

With the development of science and technology,more and more information and interest has been accumulated on microscopic,mesoscopic,and nanoscopic(molecular-scale)systems and processes.As a result,there is a natural desire to understand and control these phenomena by manipulating the operative forces.In the matter world,intermolecular forces embrace all forms of matter,and it determines the properties of simple systems such as gases,liquids,and solids,but especially of more complex,and more interesting,systems.In the absence of intermolecular interactions our world would be a uniform ideal gas.On account of its unique low-dimensional structural properties,two-dimensional graphene holds some fascinating physical properties,such as mechanical,optical and electrical characteristic.Today,graphene is believed to be able to cause sig-nificant breakthrough in the areas of energy,environment,electronic engineering,biology,etc.In this dissertation,graphene and atoms/nolecules are selected for the investi-gation.The interactions between three different types of graphene nano-strucures and atoms/molecules are studied by using the method of density functional the-ory and molecular dynamics.Additionally,we also combine the applications of graphene in energy with this study.The detailed contents are summarized and organized as follows:(1)Collisions of noble gas atoms with graphene and a graphene nanodome.The collisions of noble gas atoms with graphene and a graphene nanodome were investigated by employing ab initio molecular dynamics calculations.By analyzing the electron-related properties of the collision process.the atom dynamics and the deformation of the graphene/nanodome,our results show a difference between the elastic properties of the nanodome and graphene.Generally,the nanodome can more easily revert to its initial conformation.The final kinetic energy,Ef,of the atom that collides with the nanodome is larger than the Ef of the atom that collides with graphene.In addition,the relationship between the initial kinetic energy of the atom,EkO and its corresponding proportion of energy loss,?,is linear(except for the Kr atom).Our research will probably contribute to the investigation of the 2D materials' mechanical properties and their surface morphology.Moreover,we find that the interaction potential between atom and graphene is greatly influenced by the velocity of the incident atom.This result indicates that the atom surface collision(ACS)method can be employed to separate the isotope,and the pertinent research is carrying out.(2)Three-dimensional nanopores on monolayer graphene for hydrogen storage.Hydrogen storage in solids is becoming an ever more important technology.We theoretically design a completely new material for hydrogen storage,which is quite different from the present materials.This kind of material,base on monolayer graphene,is thought to be extremely flexible.First-principles calculations and kinetic theory of gases are employed to evaluate this material.The results demonstrate that it is promising for hydrogen storage.More than anything,the hydrogen storage capacity of this material is about 4mmol/g at 300 K and 1 atm.(3)Theoretical framework of unidirectional graphene membrane.Nanoporous graphene membrane enormous potential and excellent properties in practi-cal applications.But almost all of the previous studies were based on the assumption that the nanopores were symmetric along the normal vector of the graphene plane.A kind of graphene membrane with asymmetric semi-sphere nanopore embedded in it is designed.Its electron properties and van der Waals surface are analyzed by quantum chemistry approach.Per-meation mechanism of helium,neon and argon across this graphene mem-brane is analyzed by employing Langmuir adsorption isotherm.Molecular dynamics simulations are used to characterize the asymmetric performance of the asymmetric semi-sphere nanopore for gas permeance.The driving force of these dynamical processes is revealed by implementing noncovalent interaction analysis.These results are considered not only assist in the designing of asymmetric membrane material,but also pave the way toward the realization of unidirectional graphene membrane in the future.This dissertation is mainly about the research efforts of foundations.The pos-sibility of the applications of graphene in the energy is theoretically investigated.Meanwhile,we aim at figuring out the features of the intermolecular interactions.As a results,this research established foundations of atomic manufacturing and molecular machines.