Antioxidant Behaviors Of Graphene In The Seawater: A First-Principles Simulation

Marine corrosion is a slow chemical process and a natural phenomenon.Metal materials interact with oxygen and water,resulting in their own inefficiency and destruction.Due to seawater erosion,ships and plant equipment are damaged,daily life and production suffer serious losses.At present,the main method to prevent marine corrosion is to apply organic protective film on the metal surface to avoid the direct contact between metal and corrosive medium in the environment,reduce the risk of metal in the environment and the chemical or electrochemical reaction of metal.However,many traditional materials not only consumes a lot of non renewable energy,but also has a serious adverse impact on the sustainable development of social economy.Therefore,in the field of corrosion protection,it is a hot issue to study the metal surface coating which is harmless to the environment and has good shielding performance.In this paper,the anti-oxidation corrosion of graphene in the marine environment is simulated by density functional theory.The adsorption and diffusion mechanism of O on graphene and defective graphene and the influence of O on the adsorption and diffusion in the marine and other chlorine containing environment are clarified by using VASP software.Through the differential charge density,state density,energy band structure,diffusion energy barrier,etc.On the analysis method,it was proposed that the vacancy defect graphene doped with fluorofossil graphene and nonmetallic elements can effectively inhibit the diffusion of oxygen,so as to improve the oxidation resistance and corrosion resistance of graphene.This paper elaborates from the following aspects:1?The adsorption and diffusion of O on graphene and vacancy defect graphene were simulated,and the adsorption of Cl atom was added to simulate the influence of the adsorption and diffusion of O in the marine environment,which compared with the case without Cl,the diffusion barrier decreased by 0.13 eV,and the total energy of the system decreased by 0.55 eV.Through the analysis of energy band structure,density of States and diffusion energy barrier,it is found that the adsorbed Cl atom destroys the integrity of the structure of graphene sp2,thus greatly improving the diffusion rate of O atom.It shows that Cl atom promotes the adsorption and diffusion of O atom,which was a disadvantage factor for graphene in marine anticorrosion.2?On the basis of last study,the diffusion barrier of O atom could be increased by fluorinated graphene,it was found that the diffusion barrier of O on graphene fluoride increased by 0.13 eV,and the total energy of the system did not decrease.In the case of chlorine,the diffusion barrier of O on graphene fluoride increases by 0.61 eV and the mechanism of oxidation resistance and corrosion of fluorinated graphene in the presence of chlorine was clarified by analyzing differential charge density and energy band structure.These results provide a theoretical basis for the application of fluorofossil merene as a potential marine or marine anticorrosive material.3?The diffusion barrier of O on P,B or Si doped graphene is simulated by the first principle.It was found that P-doped graphene vacancy can increase the diffusion barrier of O most effectively.Combining Bader charge and differential charge density,the bonding properties of O,Cl and doped atoms were analyzed.The adsorption energy shows that doped P,Si or B atoms has strong binding effect on oxygen atoms,thus inhibiting the diffusion rate of oxygen.In particular,B-doped graphene has the highest diffusion barrier,which can most effectively inhibit the diffusion of O,indicating that it can provide the most effective oxidation and corrosion protection in marine and coastal environments.