Working in the Physical, Chemical, and Nano Sciences Center at Sandia National Laboratories, Tina Nenoff creates and tests molecular sponges specially tailored to capture various chemicals. Her Sandia career began with optimizing porous clay-like zeolites to absorb radioactive ions from legacy nuclear waste. Her work has expanded far beyond that in both the sponge-like materials in her arsenal and their applications.
In her core research and LDRD projects, Nenoff works closely with experts in many fields across the labs. Geoscientists and computer modeling people help design the molecular sponges. Folks in materials science determine the structure and characteristics of the resulting porous materials. Researchers take experimental results and analyze them in the context of real-world models.
Nenoff, who was included in a book highlighting the careers of 100 women in ceramic and glass science and engineering by Lynnette Madsen of the National Science Foundation, has fruitful collaborations with researchers at other national labs and in academia. She works closely with Karena Chapman and Peter Chupas at the Advanced Photon Source at Argonne National Laboratory on the structural determination of the zeolites, metal organic frameworks and other nanoporous materials. She has a longrunning collaboration with University of California, Davis, physical chemist Alexandra Navrotsky, who provides technical expertise in calorimetry, a method for characterizing how well the sponges absorb their target chemicals.
The ability to design, tune and successfully test porous crystalline materials allows for the development and commercialization of materials for many different environmental and energy applications. Metal-organic frameworks (MOFs) have shown great potential in challenging separations of molecules with very similar kinetic diameters. One area of strong focus in our lab is toward a fundamental understanding of the structure-property relationship of selective light gas adsorption in MOFs.
Here we implement a synergistic approach involving predictive molecular modeling, experimental synthesis, and synchrotron crystallographic analysis of known and novel MOF materials. Density functional theory (DFT) calculations were used to measure the binding energy for various gases on coordinatively unsaturated metal sites in MOFs. Various target gases of interest include: O2, H2, I2, Org-I, and hydrocarbons. In one example, emphasis is placed on identifying key structural features for highly selective oxygen adsorption, leading to efficiency improvements through oxy-fuel combustion. A periodic trend in oxygen binding energies was found, with early transition metals exhibiting greater oxygen binding energies compared to late transition metals; this trend was independent of MOF structural type. In another example, highly selective MOFs for I2 gas are incorporated into novel direct electrical readout sensor devices. Responses are directly related to the structure-property relationship of the MOF to the presence and quantity of adsorbed I2 molecule. Differential Pair Distribution Function (d-PDF) synchrotron and RAMAN analyses were used to determine guest-host structure relationships on both gas sorbed MOFs and temperature/pressure induced gas retention in MOFs.
Nenoff Seminar Flier