Dissertation Defense: Nicole Moehring, Interdisciplinary Materials Science
DISSERTATION DEFENSE
Nicole Moehring, Interdisciplinary Materials Science
*under the direction of Piran Kidambi
“Proton transport through 2D membranes and is applications”
08.02.23 | 3:00PM CST | 048 Engineering Science Building (ESB)
At just one atom thick, the pristine lattices of two dimensional (2D) materials, such as graphene, have unique barrier properties which enable selective transport of protons over nanoscale species. Upon introduction of defects in the graphene lattice, proton transport can be increased to reach conductance values necessary for fuel cells, vanadium redox flow batteries and other proton selective membrane applications, but if large, non-selective defects are present, selectivity is lost. Therefore, understanding and controlling angstrom-scale defects in this atomically thin material when using scalable synthesis methods such as chemical vapor deposition (CVD) is critical to advance this technology. In this dissertation, I demonstrate that the angstrom-scale defects in graphene can be controlled during CVD to achieve proton exchange membranes with tunable selectivity to sub-nanometer/nanoscale species. Methods to effectively interface graphene with proton selective polymers are evaluated and developed, providing insights critical to scaling large area membranes. Additionally, the mechanism of proton transport through 2D materials is probed experimentally using in-situ spectroscopy techniques. Further, hydrogen isotope separation (H/D) via membrane-based, electrochemical pumping is achieved and surpasses that of conventional, highly energy intensive methods.