Porous Structure, Carbon Dioxide Capture, and Separation in Cross-Linked Porphyrin-Based Polyimides Networks
journal contributionposted on 2019-07-26, 21:13 authored by Kaixiang Shi, Hongyan Yao, Shuai Zhang, Yanfeng Wei, Wenhan Xu, Ningning Song, Shiyang Zhu, Ye Tian, Yongcun Zou, Shaowei Guan
Three cross-linked porphyrin-based polyimides (PPBPI-H-CR, PPBPI-Mn-CR, and PPBPI-Fe-CR) were synthesized from 5,10,15,20-tetra(4-aminophenyl)porphyrin (TAPP) and 2,5-bis(3,4-dicarboxyphenoxy)-4′-phenylethynyl-biphenyl dianhydride (PEPHQDA) via polymerization and thermal cross-linking reactions. Their chemical structures were confirmed by FTIR and 13C CP/MAS NMR. SEM, XRD, and TEM analyses were used to observe their surface and nature characteristic morphologies as well as pore channels. DSC and TGA were carried out to confirm their cross-linking behaviors and thermal stabilities. PPBPI-H-CR showed the largest specific surface area (733 m2 g–1) and the highest CO2 uptake (2.26 mmol g–1 at 273 K and 1 bar) among the PPBPI-CRs. PPBPI-Mn-CR and PPBPI-Fe-CR compared to PPBPI-H-CR exhibited smaller specific surface areas, more uniform pore sizes around 1.2 nm, and larger isosteric heats of adsorption due to the presence of coordination sites for manganese and iron. PPBPI-CRs exhibited separation factors of CO2/N2 (31.48, 35.09, and 45.34) and CO2/CH4 (13.17, 9.06, and 12.99).
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1.2 nmCarbon Dioxide Captureuniform pore sizescoordination sitesPPBPI-CRpore channelsTAPPseparation factorssurface areasPPBPI-Fe-CRcross-linking behaviorsPorous StructureXRDCross-Linked Porphyrin-Based Polyimides NetworksDSCPEPHQDA273 KFTIRcross-linked porphyrin-based polyimideschemical structuresSEMCHCOPPBPI-H-CRCPNMRPPBPI-Mn-CRcross-linking reactions1 barTGATEM analyses