The Construction And Photocatalytic Research Of Triazine-Naphthalimide Based Covalent Organic Framework(COF)

Covalent organic frameworks（COFs）materials have a wide range of applications in photocatalysis due to their low density,high surface area and ordered pore structure.However,there are still problems such as high photoexcited charge recombination efficiency.In order to further improve the photocatalytic effect,it is necessary to select suitable strategies to modify and build COF.In this paper,triazine and naphthalimide were successfully used to construct covalent organic framework materials through solvothermal method,and this COF was further modified with PDA to investigate the potential in the field of degradation of pollutants via photocatalytic,which provided a feasible strategy for designing effective photocatalysts to achieve the degradation of organic pollutants.SystemⅠ:A triazine-naphthalimide covalent organic framework material（ACOF）with a large specific surface area and ordered crystallinity was synthesized via solvothermal method.From the results of electrochemical tests,it is evident that the ACOF has significant photocurrent changes,indicating effective photogenerated electron-hole separation.Based on this,we are encouraged to attempt to carry out experiments on the photocatalytic degradation of the organic pollutant rhodamine B.The experimental results show that more than 80%degradation can be achieved within 60 min.The possible mechanism for ACOF is that ACOF as photocatalyst absorbs photons,and thereby generates electrons and holes.The excited electrons react with oxygen to further produce·O₂^-and cooperate with h⁺to achieve degradation of pollutants.System Ⅱ:In order to further improve the effect of photocatalytic degradation,System II was designed to modify ACOF with PDA via imidation reaction.And the main design principles are following:on the one hand,the incorporation of ACOF contributes to construct heterojunction catalysts.On the other hand,the extendedπ-conjugation plane of PDA facilitates charge migration.As shown in the UV absorption spectrum,the band gap of the material became narrower and enhanced the absorption in the visible range after modifying PDA,thus improving the photocatalytic effect.Combined with the electrochemical as well as photodegradation results,more than 80%degradation of Rh B could be achieved within 1 h under the excitation of white light,which shows promise in achieving the degradation of pollutants using solar energy.