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Torquato, Nicole A.

Publications and source records attributed to Torquato, Nicole A..

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Heterogenization of Homogeneous Ruthenium(II) Catalysts for Carbon-Neutral Dehydrogenation of Polyalcohols

Liquid organic hydrogen carrier (LOHC) systems are an excellent alternative to pressurized gas and liquid hydrogen storage technologies due to their high volumetric storage capacities and straightforward adaptation to existing infrastructure. Homogeneous catalysts are promising for the selective and reversible release of hydrogen from LOHC. However, separation from product mixtures and recycling inhibit their use, particularly when comprised of costly low-abundance elements, motivating the development of heterogeneous versions that are more easily recovered and reused. Here, we describe two methods for the heterogenization of molecular Ru catalysts that efficiently dehydrogenate the polyalcohol LOHCs ethylene glycol (EG) and 1,2-propanediol (1,2-PDO). The heterogeneous versions of these catalysts maintain catalytic activity for hydrogen production comparable to the homogeneous complexes, with up to 81% conversion and 99% selectivity. Further, DFT modeling indicates mechanistic similarities for the dehydrogenations of EG and 1,2-PDO, with the rate-limiting steps associated with protonation of the Ru–H bond to form H 2 and the alkoxide species coordinated to Ru(II), followed by β-hydride elimination to regenerate the Ru–H bond. Overall, the data suggest these heterogenized molecular catalysts have potential for practical use in polyalcohol-based LOHC systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Fully Integrated Ultra-thin Intraoperative Micro-imager for Cancer Detection Using Upconverting Nanoparticles

Abstract Purpose Intraoperative detection and removal of microscopic residual disease (MRD) remain critical to the outcome of cancer surgeries. Today’s minimally invasive surgical procedures require miniaturization and surgical integration of highly sensitive imagers to seamlessly integrate into the modern clinical workflow. However, current intraoperative imagers remain cumbersome and still heavily dependent on large lenses and rigid filters, precluding further miniaturization and integration into surgical tools. Procedures We have successfully engineered a chip-scale intraoperative micro-imager array—without optical filters or lenses—integrated with lanthanide-based alloyed upconverting nanoparticles (aUCNPs) to achieve tissue imaging using a single micro-chip. This imaging platform is able to leverage the unique optical properties of aUCNPs (long luminescent lifetime, high-efficiency upconversion, no photobleaching) by utilizing a time-resolved imaging method to acquire images using a 36-by-80-pixel, 2.3 mm $$\times$$ × 4.8 mm silicon-based electronic imager micro-chip, that is, less than 100-µm thin. Each pixel incorporates a novel architecture enabling automated background measurement and cancellation. We have validated the performance, spatial resolution, and the background cancellation scheme of the imaging platform, using resolution test targets and mouse prostate tumor sample intratumorally injected with aUCNPs. To demonstrate the ability to image MRD, or tumor margins, we evaluated the imaging platform in visualizing a single-cell thin section of the injected prostate tumor sample. Results Tested on USAF resolution targets, the imager is able to achieve a resolution of 71 µm. We have also demonstrated successful background cancellation, achieving a signal-to-background ratio of 8 when performing ex vivo imaging on aUCNP-injected prostate tumor sample, improved from originally 0.4. The performance of the imaging platform on single-cell layer sections was also evaluated and the sensor achieved a signal-to-background ratio of 4.3 in resolving cell clusters with sizes as low as 200 cells. Conclusion The imaging system proposed here is a scalable chip-scale ultra-thin alternative for bulky conventional intraoperative imagers. Its novel pixel architecture and background correction scheme enable visualization of microscopic-scale residual disease while remaining completely free of lenses and filters, achieving an ultra-miniaturized form factor—critical for intraoperative settings.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

A Dicopper Platform that Stabilizes the Formation of Pentanuclear Coinage Metal Hydride Complexes

Abstract Reduction of a dicopper(II) bis(hydroxide) complex with silanes in the presence of external copper or silver cations results in the formation of multinuclear hydride clusters, which were characterized by a variety of NMR spectroscopic experiments and X‐ray crystallography. In particular, the pentanuclear complexes adopt an unusual planar “bow tie” configuration. The copper hydride complexes are efficient catalysts for the dehydrogenation of formic acid to H 2 and CO 2 .

Desnoyer, Addison N.↗
DOE OSTI2020

A Dicopper Platform that Stabilizes the Formation of Pentanuclear Coinage Metal Hydride Complexes

Abstract Reduction of a dicopper(II) bis(hydroxide) complex with silanes in the presence of external copper or silver cations results in the formation of multinuclear hydride clusters, which were characterized by a variety of NMR spectroscopic experiments and X‐ray crystallography. In particular, the pentanuclear complexes adopt an unusual planar “bow tie” configuration. The copper hydride complexes are efficient catalysts for the dehydrogenation of formic acid to H 2 and CO 2 .

Desnoyer, Addison N.↗