Controllable Synthesis And Photoelectric Properties Of Heterocyclic Pyrene Based Covalent Polymers And Their Derived Carbon Materials

Covalent organic porous materials have been widely studied in the field of materials because of their unique functionalized channel structure,low density,high specific surface area,strong stability and other advantages.They have been widely used in gas adsorption and separation,polyphase catalysis,photoelectric materials,fluorescent sensing and other fields.The design and synthesis of new photoelectric materials and fluorescent sensing materials is a hot topic.In this paper,three new covalent organic porous polymers were synthesized by using the unique pi-conjugated structure of conjugated microporous polymer materials,and their morphology,structure and thermal stability were characterized in detail to study their fluorescence detection performance and oxygen reduction performance.The following are the main contents of this article:(1)We report the synthesis and characterization of a highly luminescent conjugated microporous polycarbazole(CK-CMP)synthesized by Fe Cl₃-induced oxidative polymerization of 1,3,6,8-tetrakis(4-(9H-carbazol-9-yl)phenyl)pyrene(L).CK-CMP exhibits good thermal stability and small pore sizes.By incorporating pyrene units into CMP,the newly designed CK-CMP molecules suspended in polar solvents exhibit high luminescence upon irradiation by UV light and can be used as a sensing platform to detect 2,4,6-trinitrophenol(PA)with good sensitivity and selectivity by fluorescence quenching.As a class of conjugated polymers,polycarbazole may find application in sensing,photovoltaic cells,cell images,and photocatalysis.(2)The polymer was synthesized from 1,4-bis(4-(3,5-dicyano-2,6-dipyridinyl)-dihydropyridine benzene and Dibromo-m-xylene as structural monomers,and was doped with Fe atoms to synthesize CXL-HCP-Fe catalyst.Carbonization at different temperatures led to the formation of metal-bound HCP-derived graphene analogues.Specifically,CXL-HCP-Fe-900 exhibit remarkably enhanced catalytic properties closely comparable to the state-of-the-art Pt/C(20 wt.%)catalyst in alkaline media,and good ORR activity among the other calcined CXL-HCP-Fe-t catalysts in acidic media.In addition,CXL-HCP-Fe-900 acts as efficient electrocatalysts for oxygen reduction in both alkaline and acid media with a good stability and free from methanol-poisoning effects.This context demonstrated the CXL-HCP-Fe-900 as promising candidate for ORR catalyst with enhanced performances in energy storage and conversion.(3)The conjugated microporous polymer XWB-CMP was synthesized with 1,3,6,8-tetramethyl(tetramethyl phenyl)pyrene and dithiooxamide as structural monomers.The precursors are composed of densely populated thiazolothiazole units that uniformly decorate over the micropore surface and can be readily converted into novel N-S-DPCs with a uniform N/S distribution by template-free pyrolysis.The electrochemical characterization demonstrates that N-S-DPCs obtained at pyrolysis temperature of 1000 ^oC exhibits a high electrocatalytic activity toward oxygen reduction reaction(ORR),superior durability,good methanol tolerance as compared to the commercial Pt/C catalyst.The present work sheds insights into the effects of heteroatom doping on ORR electrocatalysts.