Theoretical Study Of Electronic Structure And Mechanism Characteristics Of Several Functional Materials

With the rapid development of industry and science and technology,more and more researchers are devoted to finding nanomaterials with high-efficiency and functionality to solve the increasingly serious problems of energy crisis and environmental pollution.The rapid development of carbon-based materials has received extensive attention in catalysis and batteries.The catalyst based on carbon-based materials has a good catalytic effect in catalyzing CO oxidation,ORR reaction and water gas reaction.Lithium-ion batteries with graphite as the negative electrode have excellent performance in electrical energy storage,and can be used in mobile devices and power cars,providing a lot of convenience for people's lives.In the research of optoelectronic devices and quantum devices,silicon-based nano-luminescent materials have gradually become one of the popular materials for electronic devices combined with substrates due to their special electronic structure and optoelectronic properties.Therefore,it is of great significance to study the electronic structure and mechanism characteristics of functional nanomaterials in work.In this paper,we use the first-principles method to systematically calculate the reaction mechanism of CO oxidation of a single Rh atom embedded in graphdiyne(GDY),explored the N-doped graphene and Zn O composite structure adsorption of Li atoms,and the electronic structural properties of one-dimensional chain(Si O₂)₁₀molecules.The main results are as follows:1.The first-principles calculations were used to systematically study the oxidation of CO by O₂on Rh-graphite(Rh-GDY).It is found that Rh atoms can exist stably in GDY as a single metal atom bound to carbon atoms,and are uniformly distributed.In our calculations,we find that both the Langmuir-Hinshelwood(LH)mechanism and the Eley-Rideal(TER)mechanism are desirable because their energy barriers for the speed-limiting steps are very low(0.54 e V and 0.49 e V,respectively).Moreover,according to their reaction rate constants at various temperatures,we find that the increase of the transition temperature,the reaction rate of the LH mechanism and the TER mechanism increase at the same time,indicating that the embedding of Rh atoms into GDY at high temperatures can promote the reaction.And after comparing the rate constants,we predict that the LH mechanism may be more preferable than the TER mechanism.Our research will translate into the oxidation mechanism of CO on SAC and provide inspiration for the design of SAC based on GDY sheet in various applications.2.Through first-principles calculations,we found that pyrrole N-doped graphene and pyridine N-doped graphene have stronger adsorption capacity for Li atoms than pure graphene.Which shows that the doping of pyrrole N and pyridine N improves the adsorption capacity of graphene to Li atoms.When different N-doped graphene and Zn O structures are compounded,the adsorption capacity of Li atoms is significantly enhanced,indicating that the N-doped graphene and Zn O composite structure is more lithium-philic and can guide the smooth deposition of Li atoms.3.The B3LYP method of density functional theory is used to calculate the ground state structure configuration of(Si O₂)₁₀molecule,to study the characteristics and laws of the influence of the applied electric field on the electronic structure of the molecule.The TD-B3LYP method was used to calculate and analyze the effect of the applied electric field on the excitation characteristics of(Si O₂)₁₀molecules.When the applied electric field is positive,as the electric field strength increases,the bond length of the Si-O bond on one side of each constituent unit of(Si O₂)₁₀molecule increases,and the other side decreases.In contrast,when the applied electric field is negative,as the electric field strength increases,the Si-O bond of each constituent unit of(Si O₂)₁₀molecules decreases on one side and increases on the other side.And as the electric field strength increases,the energy gap of(Si O₂)₁₀molecule is correspondingly decreased,which is conducive to the excitation of orbital electrons.After the application of an electric field,the excitation energy of each excited state of(Si O₂)₁₀molecules will decrease with the increase of the intensity of the applied electric field,and the wavelength of the absorption line will also have a certain red shift.