Research Of Photocatalyst G-C₃N₄ Using First Principles

From the point of view of theoretical calculation,all kinds of modification researches of g-C3N4 have been studied and the understanding of g-C3N4 photocatalyst can be further improved,thereby guiding the design and development of new photocatalysts.From different sites of doping,it constructs and calculates the photocatalytic properties of doped models including interstitial doping and substituted doping.The interrelated analysis has been carried out including the position of impurity energy level,the specific sources of impurity energy level,the influence of impurity atom on the surrounding atoms,the impact mechanism and macroscopic optical properties.A series of investigations have been carried out on g-C3N4 triazine ring,tri-s-triazine ring,the substituted doping model and interstitial doping model.F ion doping makes the optical response of tri-s-triazine ring photocatalyst optimize significantly in the visible region,due to the introduction of F ion with a charge effect,similarly liking the role of an applied electric field.The interstitial doping of Ag in the cavity can form a coordination bond with the lone pair electrons of the surrounding nitrogen atoms,and the coordination bond makes the Ag atom in the cavity stable.After the replacement of C atom by N atom,the structure is still planar and all the atomic orbits involved are sp2 hybrid types.The impurity peak originates from the delocalized large ? bond formed by the interaction of pz orbitals of C and N atoms.When the Si atom replaces the N atom,the Si atom only forms three covalent bonds with the surrounding C atoms,leaving one valence electron.The excess valence electron is free from covalent bonds and can become a free electron easily.The Si atom is positively charged and becomes a positive ion.In the system,electrons become the majority carriers,and the electrical conductivity and visible light photocatalytic activity of the system is changed correspondingly.