Tuning the Kinetic Water Stability and Adsorption Interactions of Mg-MOF-74 by Partial Substitution with Co or Ni

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• 作者：Yang Jiao ; Cody R. Morelock ; Nicholas C. Burtch ; William P. Mounfield III ; Julian T. Hungerford ; Krista S. Walton
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2015
• 出版时间：December 16, 2015
• 年：2015
• 卷：54
• 期：49
• 页码：12408-12414
• 全文大小：333K
• ISSN：1520-5045

文摘

Varying amounts of Co and Ni were substituted into the metal鈥搊rganic framework Mg-MOF-74 via a one-pot solvothermal reaction, and the effects of these substitutions on CO₂ adsorption and kinetic water stability properties were examined. Based on elemental analyses, Co and Ni are more favorably incorporated into the MOF-74 framework from solution than Mg. In addition, reaction temperature more strongly impacts the final metal composition in these mixed-metal (MM) MOF-74 structures than does the reaction solvent composition. Single-component CO₂ adsorption isotherms were measured for the MM-MOF-74 systems at 5, 25, and 45 掳C, and isosteric heats of adsorption were calculated. These results suggest that CO₂ adsorption properties can be adjusted by partial metal substitution. Water adsorption isotherms were also measured for the MM-MOF-74 samples, with powder X-ray diffraction patterns and Brunauer鈥揈mmett鈥揟eller surface areas measured both before and after water exposure. Results show that Mg-MOF-74 can gain partial kinetic water stability by the incorporation of Ni²⁺ or Co²⁺ metal ions that are less vulnerable to hydrolysis than Mg²⁺. Of particular note, Mg鈥揘i-MM-MOF-74 shows a significant increase in water stability when incorporating as little as 16 mol % Ni into the Mg-MOF-74 structure.