Hydrogen Storage in Microporous Hypercrosslinked Organic Polymer Networks

Abstract

A series of hypercrosslinked polymer networks has been synthesized by the self-condensation of bischloromethyl monomers such as dichloroxylene (DCX), 4,4‘-bis(chloromethyl)-1,1‘-biphenyl (BCMBP), and 9,10-bis(chloromethyl)anthracene (BCMA). These materials are predominantly microporous and exhibit Brunauer−Emmett−Teller (BET) surface areas of up to 1904 m2/g as measured by N2 adsorption at 77.3 K (Langmuir surface area = 2992 m2/g). Networks based on BCMBP exhibit a gravimetric storage capacity of 3.68 wt % at 15 bar and 77.3 K, the highest yet reported for an organic polymer. The micro- and mesostructure of the networks is explained by a combination of solid-state NMR, gas sorption measurements, pycnometry, and molecular simulations. The isosteric heat of sorption for H2 on these materials is found to be in the range 6−7.5 kJ/mol. A molecular model is presented for a p-DCX network that simulates well certain key physical properties such as pore volume, pore width, absolute density, and bulk density. This...