Ammonia Adsorption On Cu-MOF: a Molecular Simulation Approach

The adsorption of ammonia on HKUST-1 (a metal-organic framework, MOF) at different temperatures was investigated in both density functional theory (DFT) method grand canonical Monte Carlo (GCMC) calculation.   The calculated adsorption isotherms, the isosteric heats of adsorption were compared with those obtained from experiments. The strong adsorption of ammonia caused by chemical interactions with copper sites of HKUST-1 are evidenced by DFT results and the experimental isosteric heats of adsorption. Compared with the experimental results, higher adsorption capacities are predicted in the GCMC calculations. This discrepancy is assigned to the collapse of the MOF structure upon exposure to ammonia, and the remaining of water molecules that are bonded to copper sites during HKUST-1 synthesis.