First principles calculations were performed in collaboration with co-author Prendergast, a nanostructures theorist also with Berkeley Lab's Materials Sciences Division, to provide a theoretical model as to what should happen inside Mg-MOF-74 during adsorption of carbon dioxide.
"The calculations were a great aid in interpreting our spectra," Drisdell says. "Not only could we reproduce the spectral signatures we observed upon adsorption, but we could show that these signatures arise from a specific, distorted electronic state at the open metal sites that displays a unique interaction with different adsorbed molecules."
With their results having established NEXAFS spectroscopy as an effective experimental tool for the study of MOFs and gas adsorption, Kortright expects to see many more studies of fundamental adsorption interactions inside of MOFs.
"Regarding open metal site MOFs, similar studies in which the metal species are transition metals will be interesting, as will systematic studies of different metal sites in the same MOF structure," he says. "Such studies should provide fundamental insights and help explain why some MOFs work better than others. This, in turn, should help us to predict which are the best metals to consider as MOF design evolves."
In addition to the ALS, Kortright, Drisdell and their colleagues also called upon the resources of the National Energy Research Scientific Computing Center (NERSC)'s "Lawrencium" supercomputer and the Molecular Foundry computing clusters "Nano" and "Vulcan" for the first principles calculations. Like the ALS, NERSC and the Molecular Foundry are DOE national user facilities hosted by Berkeley Lab.
"This study is an excellent example of a collaborative team of scientists from different areas working to complete a project that none could have done in isola
|Contact: Lynn Yarris|
DOE/Lawrence Berkeley National Laboratory