Hydrogen Storage in Metal-organic Microporous Structures

Abstract

The main objective of this article is to give an overview of MOFs, which have been studied and developed with respect to the ability to store hydrogen. In the last years different synthetic approaches and conditions, namely solvothermal and hydrothermal; electrochemical and microwave roots; crystallization in biphasic solvent mixtures are applied in order to produce metal-organic microporous materials with attractive for hydrogen storage properties. In the present work hydrogen storage capacity and interaction energy of the metal-organic internal wall structure with hydrogen are considered in relation to the pore size, pore geometry and type of metal ion and ligand. Special attention has been paid to the interactions between open metal sites in MOFs and adsorbed hydrogen. The failure of these to meet the necessary for room temperature adsorption conditions has been attributed to the lack of significant orbital interactions with adsorbed H2, which makes such adsorption sites energetically similar to organic linkers and oxygen ligands, where electrostatic and dispersive forces are dominant. Keywords: Hydrogen storage, Interaction energy, MOFs, Pore size, metal hydrides, THERMODYNAMICS, enthalpy, SORPTION, dimethylformamide, isoterms