(178h) The Role of Pore Size and Polar Functional Groups in Hydrogen Adsorption in Metal Organic Frameworks

Efficient storage of hydrogen is an important aspect in utilizing hydrogen as a pollution free energy source. The adsorptive storage of molecular hydrogen on microporous materials plays a vital role in current studies and Metal-organic frameworks (MOFs) are one of the best hydrogen adsorbents, which exhibit high hydrogen adsorption uptakes. Isoreticular Metal-organic frameworks (IRMOF) materials which consist of zinc oxide clusters connected by organic linker molecules, have nanoscale pores and large surface area, that result in high hydrogen adsorption.

The objective of this study is to model adsorption of hydrogen in IRMOF-1, IRMOF-2, IRMOF-3, IRMOF-7, IRMOF-8, IRMOF-10, variants of IRMOF-10 with amine groups at two positions and Bromine at two positions by Path Integral Grand Canonical Monte Carlo (PI-GCMC) simulations using standard force fields. From the simulations, hydrogen adsorption isotherms at 300K and 77 K are generated for low pressure conditions (up to 10 atm). Isotherms generated are in fairly good agreement with existing experimental data and other simulation data. We characterize the effect of pore size and the presence of polar functional groups (amines and Bromine) on the adsorption isotherms.

Keywords: hydrogen adsorption, PI-GCMC simulation, adsorption isotherm, MOF, IRMOF