Preparation And Photocatalytic Properties Of Porphyrin-based Porous Organic Polymers

Porphyrins are a class of macrocyclic aromatic compounds formed by alternating connection of four pyrrole rings through methylene.They are widely used in the field of photocatalysis due to their good absorption of visible light and special photophysical properties.However,small molecular porphyrins are easy to aggregate in water,resulting inπ-πstacking,which hinders the contact between oxygen molecules and reduces the generation efficiency of photocatalytic active substances.And small molecule porphyrins are difficult to separate from water,resulting in secondary pollution.In order to solve these problems,porphyrin was introduced into conjugated microporous polymers（CMPs）as a structural unit in this paper.Due to the insolubility of CMPs,porphyrin can be easily separated in the recovery process to avoid secondary pollution.CMPs with highly ordered skeleton arrangement can avoid porphyrin aggregation,thereby enhancing the utilization of visible light and improving the photocatalytic efficiency of the material.The specific research contents are as follows:1.Four porphyrin-based conjugated microporous polymers were synthesized by solvothermal method using 5,10,15,20-tetra（4-aminophenyl）porphyrin（TAPP）and5,10,15,20-tetra（4-aminophenyl）copper porphyrin（Cu TAPP）as structural units and reacting with the linker 2,5-dimethoxyl-1,4-cyclohexanedione（DMSS）and tris（4-formylbiphenyl）amine（NBC）,respectively.They are porphyrin and copper porphyrin conjugated microporous polymers（H₂TD-CMP and Cu TD-CMP）linked by DMSS,and porphyrin and copper porphyrin conjugated microporous polymers（H₂TN-CMP and Cu TN-CMP）linked by NBC.The structure and physical properties of porphyrin-based conjugated microporous polymers were characterized by a series of characterization methods such as FT-IR,¹³C NMR,XPS,XRD and nitrogen adsorption-desorption.2.The adsorption properties of H₂TD-CMP and Cu TD-CMP on Rhodamine B（Rh B）under dark conditions were studied.Among them,Cu TD-CMP showed better adsorption performance and adsorption cycle stability.The adsorption rate of Rh B was 99.1%within120 min,and the adsorption rate of Rh B was still higher than 95%after three adsorption cycles.The photocatalytic performance of H₂TD-CMP and Cu TD-CMP on Rh B under visible light was studied.Cu TD-CMP showed better photocatalytic degradation performance and photocatalytic cycle stability.The photodegradation rate of Rh B was 95.8%within 180 min.After three photocatalytic cycle experiments,the photodegradation rate of Cu TD-CMP on Rh B was still higher than 93%,indicating that the material had good photocatalytic cycle stability..Free radical capture experiments showed that the main active substances of Cu TD-CMP in photocatalytic degradation were·OH,·O^2-and ¹O₂.3.The adsorption properties of H₂TN-CMP and Cu TN-CMP on Rh B under dark conditions were studied.Among them,Cu TN-CMP showed better adsorption performance and adsorption cycle stability.The adsorption rate of Rh B was 91.2%within 180 min,and the adsorption rate of Rh B was still higher than 87%after three adsorption cycles.The photocatalytic performance of H₂TN-CMP and Cu TN-CMP on Rh B under visible light was studied.Cu TN-CMP showed better photocatalytic degradation performance and photocatalytic cycle stability.The photodegradation rate of Rh B was 97.5%within 180 min.After three photocatalytic cycle experiments,the photodegradation rate of Rh B by Cu TN-CMP was still higher than 94%,indicating that the material had good photocatalytic cycle stability.Free radical capture experiments showed that the main active substances of Cu TN-CMP in photocatalytic degradation were·OH,·O^2-and ¹O₂。...