(5dc) Metal-Organic Frameworks for Energy Applications

Metal-organic frameworks (MOFs) are a new class of nanoporous materials that have potential applications in energy storage, separation processes, catalysis, and sensing. MOFs are inorganic-organic hybrids that are synthesized using organic linker molecules and metal joints that self-assemble to form materials with well-defined pores, high surface areas, and tunable chemical functionalities. By judiciously choosing the metal cluster and organic linker, MOFs can be designed such that the materials have desired magnetic, optical, catalytic, or selective adsorption properties.

My research has focused on the application of MOFs in the energy field. I particularly worked on CO2 capture from flue gas and hydrogen storage. Concerns about greenhouse gases in the atmosphere have led to significant interest in removing CO2 from the exhaust streams of fossil fuel combustion as the first step in carbon sequestration. Revolutionary advancements are needed to improve the efficiency and cost effectiveness of CO2 capture technologies. By using a combined experimental and modeling approach we screened a diverse collection of MOFs for CO2 capture from flue gas. The diversity of the chosen MOFs was critical for improving our understanding of CO2 capture in MOFs. We also used this data to validate a generalized strategy for molecular modeling of CO2 and other small molecules in MOFs.

MOFs have also shown great potential for the storage of hydrogen, which is a potential energy carrier for various applications. One major shortcoming of these materials is that hydrogen is bound only weakly at room temperature due to the fact that in classical MOFs with fully coordinated metal ions the metal-hydrogen interaction is largely screened. This necessitates cryogenic operation temperatures to obtain a significant amount of hydrogen adsorption. One way of increasing the binding energy is to create MOFs with unshielded metal-hydrogen interactions. Using molecular modeling we tested several MOFs having coordinatively unsaturated metal sites or extraframework metal ions.

My presentation will include key findings from our research on how to improve CO2 capture from flue gas, and increase the binding energy between MOFs and hydrogen for improved room temperature storage.