Synthesis, characterization and hydrogen adsorption properties of metal-organic framework Al-TCBPB

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• 作者：Dipendu Saha ; ^{dipendus@gmail.com} ; ^{sahad@ornl.gov} ; Renju Zacharia ; Lyubov Lafi ; Daniel Cossement ; Richard Chahine
• 关键词：Metal&ndash ; organic framework ; Al-TCBPB ; Pore texture ; Hydrogen adsorption
• 刊名：International Journal of Hydrogen Energy
• 出版年：2012
• 期刊代码：42_03603199
• 类别：ch
• 出版时间：March, 2012
• 卷：37
• 期：6
• 页码：5100-5107
• 文件大小：612 K

摘要

In this work, a new metal-organic framework (MOF) was synthesized by using a large organic ligand 1,3,5-tris[4鈥?carboxy(1,1鈥?biphenyl)-4-yl] benzene (abbreviated as TCBPB) and aluminum as the metal that forms the secondary building unit (SBU) by solvothermal method. The MOF, named as Al-TCBPB, was characterized with pore textural properties, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Raman and FT-IR spectroscopy. Hydrogen adsorption was measured volumetrically at ambient pressure and temperatures of 77, 88 and 298 K and at high pressure (up to 9 MPa) for temperatures 77 and 298 K. Pore textural properties revealed a high BET surface area of 2311 m²/g, narrow bimodal pore widths of 11.8 脜 and 20 脜 and a total pore volume of 0.80 cm³/g. PXRD identified the crystal structure as monoclinic with space group c2/m. This MOF adsorbs 1.53 and 0.83 wt.%of hydrogen at 77 and 88 K, respectively, and pressures up to ambient conditions. At higher pressure of 9 MPa, it demonstrated an excess adsorption of 4.8 and 1.4 wt.%at 77 and 298 K, respectively; these high-pressure data fit well with modified Dubinin-Astakov (D-A) analytical model. The heat of adsorption values of Al-TCBPB vary between 5.9 and 4.9 kJ/mol for the hydrogen adsorption loading of 0.1-0.8 wt.%and decreases monotonically to approximately 2 kJ/mol when the adsorption loading becomes 4.8 wt%.