Tarnuma Tabassum Completes Her Ph.D. for "Applying Magnetic Resonance Spectroscopic Techniques to Elucidate Structure-Property Relationships in Silica-Based Surfaces"

Tarnuma joined the Han Lab in 2015 after graduating from Mount Holyoke College. Under the direction of Prof. Susannah Scott and Prof. Songi Han, Tarnuma's research focus has been on the characterization of supported catalytic materials. By using advanced magnetic resonance techniques, including both EPR and NMR, Tarnuma investigates the structural driving forces and underlying mechanisms that dictate kinetic effects in reactions.   Tarnuma’s dissertation is on the topic "Applying Magnetic Resonance Spectroscopic Techniques to Elucidate Structure-Property Relationships in Silica-Based Surfaces". Obtaining molecular-level structural information about heterogeneous catalysts and catalyst supports such as silicas and all-silica zeolites (zeosils) is critical for the rational design of new catalysts. Zeosils modified with H₃PO₄, referred to as P-zeosils, selectively catalyze the dehydration of biomass-derived alcohols, but are unstable in the presence of water. The nature of the active P-sites in these catalysts, and how they are impacted by water is not known.   During her defense, Tarnuma discussed the spatial distribution of these silanol sites on silica surfaces, typically used to increase the fraction of non-interacting silanols for well-defined active sites, investigated using VCl₄ as a paramagnetic probe molecule. Additionally, Tarnuma  demonstrated how the P-site distribution in a P-modified self-pillared pentasil (P-SPP) was probed using solid-state ³¹P MAS NMR with frequency-selective detection, dynamic nuclear polarization-enhanced ²⁹Si-filtered ³¹P detection and ³¹P-³¹P correlation experiments. In addition, Tarnuma demonstrated the effect of the zeosil framework on the stability of the P-sites determined by comparing the solid-state ³¹P and ultrafast ¹H MAS-NMR of P-SPP to that of a hydrophobic P-modified BEA zeosil (P-BEA).   Tarnuma will now be taking on a job at PPG in Allison Park, PA as an S&T research chemist. Tarnuma will be greatly missed by all members of the Han Lab.   Congratulations again, Dr. Tarnuma Tabassum!