A theoretical study of activated nanostructured materials for hydrogen storage

Abstract

The adsorption of molecular hydrogen on activated nanostruture materials is studied through computational simulations based on the pseudopotential density functional method. The hydrogen sorption energy and its diffusion through chemically activated pores in the materials are particularly investigated. It is found that the sorption energy of hydrogen reaches as high as about 29 kJ/mol at activated sites and can be controlled by modifying the structure and chemistry of the pores. The equilibrium pressure of hydrogen adsorption is also presented as a function of temperature by including the temperature and pressure dependence of hydrogen entropy. The desorption temperature is estimated to be close to 270 K for optimized activated nanostructures. This study demonstrates a pathway of materials search based on computational simulations for proper media that can hold hydrogen at ambient conditions through physisorption. (c) 2006 Elsevier B.V. All rights reserved.