Size Engineering of Metal-Organic Framework MIL-101(Cr) for CO2 Adsorption

Julia P. Hart and Mariam N. Ismail, Department of Chemistry and Physics, Simmons University, 300 Fenway, Boston MA 02115

The overuse of fossil fuels has resulted in excessive CO2 emissions, reaching a historic level of 412 ppm in September of 2019. Although technologies have been developed for the decrease in levels of atmospheric CO2, the material activity is oftentimes limited to adsorption and capture. Metal-organic frameworks (MOFs) have emerged as a solution to this limitation, providing means for catalysis driven molecule conversion into advantageous products. This improvement can be attributed to the intrinsic characteristics of MOFs: large surface area, well-ordered porosity, structural diversity, and tunability. Furthermore, MOFs can be altered (e.g. amine modification) for enhanced molecule selectivity and increased visible light (~45% solar energy) activity, in comparison to typical UV light (~5% solar energy) driven catalysis. Among these materials, the MILs (Materials of Institute Lavoisier) have attracted considerable attention; MIL-101(Cr), consisting of chromium ions cross-linked with 1,4-benzene dicarboxylate, presents a large surface area and enhanced chemical/thermal stability, qualities favorable of stable reaction kinetics, material efficacy, and system reusability. Four MOF crystal types will be presented: (1) MIL-101(Cr) at 200nm; (2) MIL-101(Cr)-EN at 200nm; (3) MIL-101(Cr) at <1000nm; (4) MIL-101(Cr)-EN at <1000nm. A typical synthesis procedure involved mixing Cr(NO3)3•9H2O (2.006g, 5mmol), terephthalic acid (0.836g, 5mmol), and 20 mL DI water. The resulting dark-blue suspension was placed in a Teflon-lined autoclave and heated at 218ºC for 18 hours. The synthesized MIL-101(Cr) solids were washed by centrifugation with water, methanol, and acetone, followed by vacuum drying for 2 days under ambient conditions. All products were characterized by XRD, TEM, SEM, FTIR, and H1NMR. Carbon dioxide and nitrogen adsorption isotherms will be utilized to measure the specificity of synthesized products. The effects of amine functionalization, size, and synthesis method of MIL-101(Cr) will also be discussed.

Additional Abstract Information

Presenter: Julia Hart

Institution: Simmons College

Type: Poster

Subject: Chemistry

Status: Approved

Time and Location

Session: Poster 4
Date/Time: Tue 11:00am-12:00pm
Session Number: 3531