Adsorption and Diffusion of Hydrogen in a New Metal−Organic Framework Material:  [Zn(bdc)(ted)_0.5]

We have experimentally measured hydrogen isotherms at 77 and 298 K up to a hydrogen pressure of 50 bar in a recently developed metal−organic framework material, [Zn(bdc)(ted)0.5] (bdc = benzenedicarboxylate, ted = triethylenediamine). This material has a tetragonal structure and relatively small pores. We have used atomically detailed simulations to compute adsorption isotherms of hydrogen over the same temperature and pressure ranges studied experimentally. The agreement between experiments and simulations is very good. We have included quantum effects through the Feynman−Hibbs effective potential approach; quantum effects must be included at 77 K to achieve agreement with experiments. We have used equilibrium molecular dynamics to compute self- and transport diffusivities of hydrogen in [Zn(bdc)(ted)0.5] at both 77 and 298 K over a range of pore loadings. Quantum effects are found to decrease the self-diffusivity compared with classical simulations at fixed loading. Conversely, at fixed pressure, quantum effects lead to a lower loading and therefore a higher self-diffusion coefficient compared with classical simulation results. Transport diffusivities with and without quantum corrections are essentially indistinguishable. The diffusivities for H2 in [Zn(bdc)(ted)0.5] are comparable to H2 in IRMOF-1 at 298 K.