A5050679087- Advanced NMR Techniques and Applications
- Solid-state spectroscopy and crystallography
- NMR spectroscopy and applications
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Muon and positron interactions and applications
- Atomic and Subatomic Physics Research
- Zeolite Catalysis and Synthesis
- Electron Spin Resonance Studies
- Organometallic Complex Synthesis and Catalysis
- Advanced Battery Materials and Technologies
- Chemical Synthesis and Characterization
- Asymmetric Hydrogenation and Catalysis
- Inorganic Fluorides and Related Compounds
- Chemical Reactions and Isotopes
- Advanced MRI Techniques and Applications
- Catalysis and Oxidation Reactions
- Rare-earth and actinide compounds
- Catalytic Processes in Materials Science
- Metal-Organic Frameworks: Synthesis and Applications
- Nanomaterials for catalytic reactions
- Molecular spectroscopy and chirality
- Advancements in Battery Materials
- Boron Compounds in Chemistry
- Organoboron and organosilicon chemistry
Ames National Laboratory
2016-2025
Iowa State University
2015-2025
NOAA Chemical Sciences Laboratory
2025
Boston College
2022
United States Department of Energy
2018-2021
Northwestern University
2018
University of Ottawa
2009-2017
Institute of Catalysis and Petrochemistry
2015
Centre for Catalysis Research and Innovation
2015
Ottawa University
2014
Our civilization relies on synthetic polymers for all aspects of modern life; yet, inefficient recycling and extremely slow environmental degradation plastics are causing increasing concern about their widespread use. After a single use, many these materials currently treated as waste, underutilizing inherent chemical energy value. In this study, energy-rich polyethylene (PE) macromolecules catalytically transformed into value-added products by hydrogenolysis using well-dispersed Pt...
Cesium lead halide perovskite quantum dots (QDs) have gained significant attention as next-generation optoelectronic materials; however, their properties are highly dependent on surface chemistry. The surfaces of cuboidal CsPbBr3 QDs been intensively studied by both theoretical and experimental techniques, but fundamental questions still remain about the atomic termination QDs. binding sites modes ligands at unproven. Herein, we demonstrate that solid-state NMR spectroscopy allows...
Abstract Carbon–carbon bond cleavage reactions, adapted to deconstruct aliphatic hydrocarbon polymers and recover the intrinsic energy carbon value in plastic waste, have typically been catalysed by metal nanoparticles or air-sensitive organometallics. Metal oxides that serve as supports for these catalysts are considered be inert. Here we show Earth-abundant, non-reducible zirconia catalyses hydrogenolysis of polyolefins with activity rivalling precious nanoparticles. To harness this...
ADVERTISEMENT RETURN TO ISSUEViewpointNEXTDynamic Nuclear Polarization Solid-State NMR in Heterogeneous Catalysis ResearchTakeshi Kobayashi†, Frédéric A. Perras†, Igor I. Slowing†‡, Aaron D. Sadow†‡, and Marek Pruski*†‡View Author Information† U.S. DOE Ames Laboratory, Ames, Iowa 50011-3020, United States‡ Department of Chemistry, State University, States*E-mail: [email protected]Cite this: ACS Catal. 2015, 5, 12, 7055–7062Publication Date (Web):October 20, 2015Publication History Received14...
Due to its extremely low natural abundance and quadrupolar nature, the (17)O nuclide is very rarely used for spectroscopic investigation of solids by NMR without isotope enrichment. Additionally, applicability dynamic nuclear polarization (DNP), which leads sensitivity enhancements 2 orders magnitude, wrought with challenges due lack spin diffusion transfer efficiency from (1)H. Here, we demonstrate new DNP-based measurements that extend solid-state beyond current capabilities. The use...
Ice recrystallization inhibition (IRI) activity is a very desirable property for an effective cryoprotectant. This was first observed in biological antifreezes (BAs), which cannot be utilized cryopreservation due to their ability bind ice. To date, potent IRI active compounds have been limited BAs or synthetic C-linked AFGP analogues (1 and 2), all of are large peptide-based molecules. paper describes the example low molecular weight carbohydrate-based derivatives that exhibit activity....
The coefficient of thermal expansion ZrMgMo3O12 has been measured and was found to be extremely close zero over a wide temperature range including room (αl = (1.6 ± 0.2) × 10–7 K–1 from 25 450 °C by X-ray diffraction (XRD)). belongs the family AMgM3O12 materials, for which coefficients have previously reported low-positive low-negative. However, low property had not explained because atomic position information available any members this materials. We determined structure nuclear magnetic...
Ultrawideline dynamic nuclear polarization (DNP)-enhanced 195Pt solid-state NMR (SSNMR) spectroscopy and theoretical calculations are used to determine the coordination of atomic Pt species supported within pores metal–organic frameworks (MOFs). The SSNMR spectra, with breadths reaching 10 000 ppm, were obtained by combining DNP broadbanded cross-polarization CPMG acquisition. Although enhancements in static samples lower than those typically observed under magic-angle spinning conditions,...
This is the first report of a multifunctional separator for potassium-metal batteries (KMBs). Double-coated tape-cast microscale AlF3 on polypropylene (AlF3 @PP) yields state-of-the-art electrochemical performance: symmetric cells are stable after 1000 cycles (2000 h) at 0.5 mA cm-2 and mAh , with 0.042 V overpotential. Stability maintained 5.0 600 (240 h), 0.138 Postcycled plated surface dendrite-free, while stripped contains smooth solid electrolyte interphase (SEI). Conventional PP fail...
Catalytic methods that introduce functional groups via carbon–carbon bond cleavage steps have typically been limited to moieties activated by strain or directing groups, with few transformations engaging the bonds of only sp3Cho J.Y. Tse M.K. Holmes D. Maleczka R.E. Smith M.R. Remarkably selective iridium catalysts for elaboration aromatic C-H bonds.Science. 2002; 295: 305-308Crossref PubMed Scopus (900) Google Scholar-hybridized carbon atoms in saturated hydrocarbons. Here, we report...
QUEST for chlorine: The chemical shifts and quadrupolar asymmetry parameters obtained from solid-state 35Cl NMR spectroscopy can be related to the nature of ClC bond (see picture) crystal packing environment Cl atoms that are covalently bound carbon atoms. A method exact calculation spectra, named QUEST, was developed used analysis seven different compounds. 35/37Cl studies organic systems very rare, with only a few neat liquids having been studied.1 lack chlorine data may explained by fact...
Heterogeneous Brønsted acid catalysts are tremendously important in industry, particularly catalytic cracking processes. Here we show that these sites can be directly observed at natural abundance by 17 O DNP surface-enhanced NMR spectroscopy (SENS). We additionally the O-H bond length measured with sub-picometer precision, to enable a direct structural gauge of lability protons given material, which is correlated pH zero point charge material. Experiments performed on materials impregnated...
Dynamic nuclear polarization (DNP)-enhanced solid-state magnetic resonance (SSNMR) spectroscopy is increasingly being used as a tool for the atomic-level characterization of surface sites. DNP surface-enhanced SSNMR materials has, however, been limited to studying relatively receptive nuclei, and particularly rare 17O nuclide, which great interest science, has not utilized. We demonstrate that advanced experiments can be performed on species at natural isotopic abundance using DNP. use 2D...
The characterization of nanometer-scale interactions between carbon-containing substrates and alumina surfaces is paramount importance to industrial academic catalysis applications, but it also very challenging. Here, we demonstrate that dynamic nuclear polarization surface-enhanced NMR spectroscopy (DNP SENS) allows the unambiguous description coordination geometries conformations at surface through high-resolution measurements 13C-27Al distances. We apply this new technique elucidate...
Lignocellulosic biomass is a promising sustainable feedstock for the production of biofuels, biomaterials, and biospecialty chemicals. However, efficient utilization has been limited by our poor understanding its molecular structure. Here, we report dynamic nuclear polarization (DNP)-enhanced solid-state (SS)NMR study structure biomass, both pre- postcatalytic treatment. This technique enables measurement 2D homonuclear 13C–13C correlation SSNMR spectra under natural abundance, yielding,...
Well-defined organoplatinum(IV) sites were grafted on a Zn(II)-modified SiO2 support via surface organometallic chemistry in toluene at room temperature. Solid-state spectroscopies including XAS, DRIFTS, DRUV-vis, and solid-state (SS) NMR enhanced by dynamic nuclear polarization (DNP), as well TPR-H2 TEM techniques revealed highly dispersed (methylcyclopentadienyl)methylplatinum(IV) the ((MeCp)PtMe/Zn/SiO2, 1). In addition, computational modeling suggests that reaction of (MeCp)PtMe3 with is...
The sensitivity of NMR spectroscopy is considerably enhanced by dynamic nuclear polarization (DNP). In DNP transferred from unpaired electrons a polarizing agent to nearby proton spins. solids, this transfer followed the transport hyperpolarization bulk via 1 H-1 H spin diffusion. efficiency these steps critical obtain high gains, but pathways for in region near electron spins are unclear. Here we report series seven deuterated and one fluorinated TEKPol biradicals probe effect deprotonation...
Colloidal chemistry holds promise to prepare uniform and size-controllable pre-catalysts; however, it remains a challenge unveil the atomic-level transition from pre-catalysts active catalytic surfaces under reaction conditions enable mechanistic design of catalysts. Here, we report an ambient-pressure X-ray photoelectron spectroscopy study, coupled with in situ environmental transmission electron microscopy, infrared spectroscopy, theoretical calculations, elucidate surface sites colloidal...
Catalytic C-H borylation is an attractive method for the conversion of most abundant hydrocarbon, methane (CH4), to a mild nucleophilic building block. However, existing CH4 catalysts often suffer from low turnover numbers and conversions, which hypothesized result inactive metal hydride agglomerates. Herein we report that heterogenization bisphosphine molecular precatalyst, [(dmpe)Ir(cod)CH3], onto amorphous silica dramatically enhances its performance, yielding catalyst 12-times more...
Chemical polymer upcycling by processive catalysts is a promising plastic waste remediation strategy, with the capability of producing selective, high-value products from plastics minimal energy input. We previously designed novel catalyst mesoporous SiO2 shell/Pt nanoparticle/SiO2 core architecture (mSiO2/Pt/SiO2) that deconstructs polyolefins within narrow pores. Here, we elucidate mechanism polyolefin hydrogenolysis using in situ magic-angle spinning (MAS) nuclear magnetic resonance (NMR)...
Abstract Microstructure of argyrodite solid‐state electrolyte (SSE) critically affects lithium metal electrodeposition/dissolution. While the stability unmodified SSE is mediocre, once optimized state‐of‐the‐art electrochemical performance achieved (symmetric cells, full cells with NMC811) without secondary interlayers or functionalized current collectors. Planetary mechanical milling in wet media (m‐xylene) employed to alter commercial Li 6 PS 5 Cl (LPSCl) powder. Quantitative stereology...
Single-site supported organometallic catalysts bring together the favorable aspects of homogeneous and heterogeneous catalysis while offering opportunities to investigate impact metal–support interactions on reactivity. We report a (dmPhebox)Ir(III) (dmPhebox = 2,6-bis(4,4-dimethyloxazolinyl)-3,5-dimethylphenyl) complex chemisorbed sulfated zirconia, molecular precursor for which was previously applied hydrocarbon functionalization. Spectroscopic methods such as diffuse reflectance infrared...