Synthesis Of 3D Covalent Organic Frameworks Based On Pd/Ni Porphyrin For Photocatalysis

Covalent organic frameworks(COFs)are a kind of porous crystalline material connected by covalent bonds with high surface area,low density and adjustable pore size,which can be widely used in gas adsorption and separation,catalysis and so on.The main research works of COFs are focused on the design of new topology and the application of functionalized COFs.However,the construction and application of 3D COFs still remain challenges.Porphyrin compounds are a class of organic photoelectric molecules with unique photochemical and photophysical properties,which were often used as building blocks in the research of structural chemistry and material chemistry.Based on this,the research of our paper focus on the design and synthesis of metalloporphyrin 3D COFs and exploration on its application of photocatalysis,mainly including this three parts:1.Firstly,two novel three-dimensional metalloporphyrin COFs(3D-NiPor-COF,3D-PdPor-COF)and a novel two-dimensional metalloporphyrin COFs(2D-PdPor-COF)were successfully synthesized.And a series of characterization,including PXRD,infrared spectrum,thermogravimetric analysis,nitrogen adsorption and so on,were conducted to prove that these three COFs have been successfully constructed with good crystalline,porosity and thermal stability.2.And then,these COFs were used as photocatalyst in the experiment of photocatalytic oxidation of sulfides,and the difference of photocatalytic properties of COFs was investigated.The results showed that 3D-PdPor-COF had excellent photocatalytic activity and high catalytic yield for substrates with different substituent groups in this COFs,and it remained stable catalytic yield after three cycles of experiments without losing of crystallinity.3.Last,in order to further study the photocatalytic mechanism and explain the difference of COFs in the photocatalytic properties.The triplet excited state lifetime and EPR spectrum were tested,proving that 3D-PdPor-COF has long excited state life,strong ability to produce super oxygen radical and singlet oxygen.Therefore,3D-PdPor-COF has good photocatalytic properties.