Binding energy of H2 to MOF-5: A Model Study

摘要

Using models simulating the environment of two distinct adsorption sites of H2 in metal-organic framework-5 (MOF-5), binding energies of H2 to MOF-5 were evaluated at the MP2 and CCSD(T) level. For organic linker section modeled as dilithium 1,4-benzenedicarboxylate (CeF4(COO)2Li2), the MP2 and CCSD(T) basis set limit binding energies are estimated to be 5.1 and 4.4 kJ/mol, respectively. For metal oxide cluster section modeled as Zn4O(CO2H)6, while the MP2 basis set limit binding energy estimate amounts to 5.4 kJ/mol, CCSD(T) correction to the MP2 results is shown to be insignificant with basis sets of small size. Substitution of benzene ring with pyrazine ring in the model for the organic linker section in MOF-5 is shown to decrease the H2 binding energy noticeably at both the MP2 and CCSD(T) level, in contrast to the previous study based on DFT calculation results which manifested substantial increase of H2 binding energies upon substitution of benzene ring with pyrazine ring in the similar model.