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

作者：Yang Jiao, Cody R. Morelock, Nicholas C. Burtch, William P. Mounfield, Julian T. Hungerford, Krista S. Walton · 发表于：Industrial & Engineering Chemistry Research · 年份：2015 · DOI：10.1021/acs.iecr.5b03843 · 被引用次数：211 · 研究领域：Metal-Organic Frameworks: Synthesis and Applications、Covalent Organic Framework Applications、Membrane Separation and Gas Transport

Varying amounts of Co and Ni were substituted into the metal–organic framework Mg-MOF-74 via a one-pot solvothermal reaction, and the effects of these substitutions on CO 2 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 CO 2 adsorption isotherms were measured for the MM-MOF-74 systems at 5, 25, and 45 °C, and isosteric heats of adsorption were calculated. These results suggest that CO 2 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–Emmett–Teller 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 Ni 2+ or Co 2+ metal ions that are less vulnerable to hydrolysis than Mg 2+ . Of particular note, Mg–Ni-MM-MOF-74 shows a significant increase in water stability when incorporating as little as 16 mol % Ni into the Mg-MOF-74 structure.