Acta Chimica Sinica ›› 2014, Vol. 72 ›› Issue (5): 557-562.DOI: 10.6023/A14020121 Previous Articles     Next Articles



王维a, 闫卓君b, 元野b, 孙福兴b, 赵明a, 任浩b, 朱广山b   

  1. a 吉林大学材料科学与工程学院 长春 130022;
    b 吉林大学无机合成与制备国家重点实验室 长春 130012
  • 投稿日期:2014-02-20 发布日期:2014-04-13
  • 通讯作者: 赵明,任浩;
  • 基金资助:

    项目受国家自然科学基金(No. 20831002)、重大国际(地区)合作研究(No. 21120102034)、国家重点基础研究发展计划(No. 2010CB631001)资助.

Target Synthesis of a Novel Porous Aromatic Framework for Efficient CO2 Capture

Wang Weia, Yan Zhuojunb, Yuan Yeb, Sun Fuxingb, Zhao Minga, Ren Haob, Zhu Guangshanb   

  1. a Jilin University Key Laboratory of Automobile Materials, Ministry of Education, and School of Materials Science and Engineering, Jilin University, Changchun 130022;
    b Jilin University State Key Laboratory of Inorganic Synthesis & Preparative Chemistry, Jilin University, Changchun 130012
  • Received:2014-02-20 Published:2014-04-13
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 20831002), Major International (Regional) Joint Research Project (No. 21120102034), National Key Basic Research and Development Program (No. 2010CB631001).

In this report, novel porous aromatic frameworks (PAF-51) have been synthesized using tetrahedral units in the presence of zinc chloride by a facile ionothermal method. PAF-51-1 and PAF-51-2 displayed large surface areas as 720 and 557 m2·g-1 (BET) respectively. Selectivity of CO2/N2 is as high as 52.2 at 273 K and CO2/CH4 can reach 10.3 at 273 K. The properties make it a promise as the ideal candidate to capture CO2 and can be used for clean and renewable energy which still needs further study. FTIR spectra of initial monomers and final products gave us information of the reaction process. The absence of cyanogroups (2230 cm-1) of the TCDPSi can verify the completion of the trimerization reaction. The appearance of breathing vibration bands of triazine ring (1560~1520 and 1480~1350 cm-1) and out-of-plane flexural vibration (860~736 cm-1) indicate the formation of polymeric networks. Thermogravimetric analysis (TGA) under atmosphere of the two samples revealed a high thermal stability up to 415 (PAF-51-1) and 475 ℃ (PAF-51-2). Furthermore, these materials are all insoluble after long-period stirring in most common solvents, such as 1 mol/L HCl, acetone, tetrahydrofuran (THF), N,N-dimethylformamide (DMF), CHCl3, etc., showing high chemical stability. FTIR spectra of PAF-51 before stirring in these solvents (HCl, acetone, THF, DMF, and CHCl3 etc.) and after stirring in solvents were barely changed. Powder X-ray diffraction (PXRD) of these PAFs revealed no distinct diffraction peaks, indicating that these polymers are composed of an amorphous network. Scanning electron microscopy (SEM) analyses display that the polymers consist of aggregated irregular lumps with nanometer dimensions. Transmission electron microscopy (TEM) investigations show their clear porous textures and agree on the amorphous structures. The surface areas of PAF-51-1 and PAF-51-2 are 720 and 557 m2·g-1 on BET model respectively. At low relative pressure, inflection point of the isotherm of PAF-51-2 appears much earlier than PAF-51-1, which might be a suggestion of the distribution of micropores in the product. Indeed, pore size distribution calculated from nonlocal density functional theory (NLDFT) using the model of carbon as an adsorbent also demonstrates this. The pore size distribution of PAF-51-1 mainly exists in the region between 2~20 Å. Although pore size distribution of PAF-51-2 also mostly exists in the microporous region, less distribution than that in PAF-51-1, and more distribution can be found in mesoporous region between 20~500 Å. The selectivity of PAF-51-1 reaches 34.1 which was calculated from the initial slopes of the CO2 and N2 adsorption isotherms. Much more remarkably, the selectivity at room temperature (298 K) decreases very little (from 34.1 to 32.4), which is better than many other porous materials with higher surface area and CO2 uptakes. Remarkably, the selectivity of PAF-51-2 is much higher than PAF-51-1 (52.2 at 273 K and 43.6 at 298 K). Likewise, the selective adsorption of CO2 to CH4 can reach 10.3 at 273 K.

Key words: ionothermal reaction, porous aromatic framework, CO2 adsorption separation, nitrogen-rich framework