Unravelling the possibility of hydrogen storage on naphthalene dicarboxylate-based MOF linkers: a theoretical perspective

Abstract

Post-synthetic modification of organic linkers embedded in a metal–organic framework (MOF) is a favourable strategy to improve the storage of hydrogen through physisorption at ambient conditions. Density functional and domain-based local pair natural orbital coupled cluster calculations are conducted to evaluate the feasibility of hydrogen adsorption on open metal sites of a Napthalene Dicarboxylate-based linker. Both alkaline metal ions like Ca2+ and Mg2+ and transition metal ions like Zn2+ and Cd2+ are chosen for this study. DFT and DLPNO-CCSD(T) energies reveal that the Napthalene Dicarboxylate systems with open magnesium, zinc and cadmium sites are capable of reversible H2 binding. However, the adsorption energy with calcium is rather low precluding build-up of H2 on CaNDC coordination site. Furthermore, local energy decomposition analysis reveals charge transfer interaction is dominant in small ions like magnesium while exchange interaction of same spin electrons governs the complexation energy in transition metals like zinc and cadmium.