GRAPHENE OXIDE FRAMEWORK (GOF) MATERIALS: THEORETICAL PREDICTIONS AND EXPERIMENTAL RESULTS
Jacob Burress1, Gadipelli Srinivas2, Jamie Ford1, Jason Simmons1, Wei Zhou3, Taner Yildirim1,2
1) NIST Center for Neutron Research
2) University of Pennsylvania
3) University of Maryland
Graphene oxide chemistry has shown a recent resurgence in interest. Yet, there has been little attention paid to the gas storage capabilities of graphene oxide and graphene oxide based materials. We propose that by using the well-known chemistry between boronic acids and hydroxyl groups, graphene oxide layers can be linked together to form a new layered structure. This new nanoporous material, a so called graphene oxide framework (GOF), formed of layers of graphene oxide connected by benzene-boronic acid pillars is being investigated as a potential storage medium for hydrogen and other gases. Grand Canonical Monte Carlo adsorption simulations reveal that an idealized GOF structure could adsorb hydrogen up to 6 wt% at 77 K and 1 bar, a value higher than any other porous material known.
Our initial synthesized GOF materials exhibit isosteric heats at zero coverage of 9 kJ/mol and 32 kJ/mol for H2 and CO2, respectively. The nitrogen BET surface area of these initial materials is around 500 m2/g. Despite this low surface area, GOFs exhibit 1 wt% H2 uptake at 1 bar. This is much less than what the ideal GOF structure can hold, suggesting that our initial GOF materials could be significantly optimized. Powder x-ray diffraction revealed tunable interlayer spacing, reaching a maximum once the interlayer space has been saturated by linker. Neutron spectroscopy studies of graphene oxide and GOFs with in situ hydrogen loading have been performed. Results on the hydrogen dynamics in these systems will be presented. Additionally, GOF elemental composition has been determined via prompt gamma neutron activation analysis. In the future, GOF structures will be synthesized with