A5088649229- Advanced NMR Techniques and Applications
- Advanced Battery Materials and Technologies
- Advancements in Battery Materials
- Atomic and Subatomic Physics Research
- NMR spectroscopy and applications
- Advanced Battery Technologies Research
- Advanced MRI Techniques and Applications
- Electrocatalysts for Energy Conversion
- Crystallization and Solubility Studies
- Quantum, superfluid, helium dynamics
- X-ray Diffraction in Crystallography
- CO2 Reduction Techniques and Catalysts
- Asymmetric Hydrogenation and Catalysis
- Chemical Synthesis and Analysis
- Spectroscopy and Quantum Chemical Studies
- Conducting polymers and applications
- Solid-state spectroscopy and crystallography
- Electrochemical Analysis and Applications
- Lanthanide and Transition Metal Complexes
- Advanced battery technologies research
- Nonlinear Dynamics and Pattern Formation
- Boron and Carbon Nanomaterials Research
- Membrane-based Ion Separation Techniques
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Metalloenzymes and iron-sulfur proteins
Forschungszentrum Jülich
2018-2023
Max Planck Institute for Chemical Energy Conversion
2017-2021
RWTH Aachen University
2013-2018
FH Aachen
2017
Abstract NMR signal amplification by reversible exchange (SABRE) has been observed for pyridine, methyl nicotinate, N ‐methylnicotinamide, and nicotinamide in D 2 O with the new catalyst [Ir(Cl)(IDEG)(COD)] (IDEG=1,3‐bis(3,4,5‐tris(diethyleneglycol)benzyl)imidazole‐2‐ylidene). During activation hyperpolarization steps, exclusively was used, resulting first fully biocompatible SABRE system. Hyperpolarized 1 H substrate signals were at 42.5 MHz upon pressurizing solution para hydrogen close to...
Abstract Para‐hydrogen‐induced polarization (PHIP) is a technique capable of producing spin at magnitude far greater than state‐of‐the‐art magnets. A significant application PHIP to generate contrast agents for biomedical imaging. Clinically viable and effective not only require high levels but heterogeneous catalysts that can be used in water eliminate the toxicity impact. Herein, we demonstrate use Pt nanoparticles capped with glutathione induce water. The ligand‐inhibited surface...
The recent mechanistic understanding of active sites, adsorbed intermediate products, and rate-determining steps (RDS) nitrogen (N)-modified carbon catalysts in electrocatalytic oxygen reduction (ORR) evolution reaction (OER) are still rife with controversy because the inevitable coexistence diverse N configurations technical limitations for observation formed intermediates. Herein, seven kinds aromatic molecules designated single species used as model structures to investigate explicit role...
We report a trinuclear copper(II) complex, [(DAM)Cu3(μ3-O)][Cl]4 (1, DAM = dodecaaza macrotetracycle), as homogeneous electrocatalyst for water oxidation to dioxygen in phosphate-buffered solutions at pH 7.0, 8.1, and 11.5. Electrocatalytic 7 occurs an overpotential of 550 mV with turnover frequency ∼19 s–1 1.5 V vs NHE. Controlled potential electrolysis (CPE) experiments 11.5 over 3 h 1.2 8.1 40 min 1.37 NHE confirm the evolution Faradaic efficiencies 81% 45%, respectively. Rinse tests...
Abstract The development of effective and precious‐metal‐free electrocatalysts for the oxygen evolution reaction (OER) represents a major bottleneck to unlock renewable energy scenario based on water splitting technologies. Materials uniting electrical conductivity conjugated graphitic nanomaterials with chemical regularity metal‐organic‐framework (MOF) crystals are promising precursors such electrocatalysts. Nanoscale integration these two materials is challenging. A new synthesis route...
[Re]ad all about it: The first examples of the rhenium-catalyzed dehydrogenative formation amides and esters with highly active ReH5(triphos) complex are demonstrated. addition a tertiary amine additive improves selectivity stability catalyst in from primary alcohols. As service to our authors readers, this journal provides supporting information supplied by authors. Such materials peer reviewed may be re-organized for online delivery, but not copy-edited or typeset. Technical support issues...
We report new phenomena in low-field 1H nuclear magnetic resonance (NMR) spectroscopy using parahydrogen induced polarization (PHIP), enabling determination of chemical shift differences, δν, and the scalar coupling constant J. NMR experiments performed with thermal millitesla fields do not allow constants for homonuclear coupled spins inverse weak regime (δν<J). show here that PHIP enable precise δν Furthermore we experimentally prove observed splittings are related to a nonlinear way....
Electrolyte composition governs battery design due to its influence on ion dynamics, active material stability, and performance. Using electron paramagnetic resonance (EPR) nuclear magnetic (NMR), complemented by density...
Abstract Despite extensive research conducted on plating and dendrite formation in lithium batteries, the molecular processes are not yet fully understood. Electron paramagnetic resonance (EPR) sensitively detects metallic Li species but misses non-paramagnetic ones. Nuclear magnetic (NMR) is chemically selective, exhibits low sensitivity under low-field conditions. Dynamic nuclear polarization (DNP) overcomes this by transferring electron spin to nuclei. Here, correlative EPR DNP-enhanced...
Nitrogen-containing hydrothermal carbon (N-HTC) materials of spherical particle morphology were prepared by means synthesis with glucose and urotropine as precursors. The molar ratio to has been varied achieve a continuous increase in nitrogen content. By raising the glucose, maximal fraction about 19 wt % could be obtained. Decomposition products both react each other; this opens up variety possible reaction pathways. pH pronounced effect on pathway corresponding steps. For first time,...
Abstract Para‐hydrogen‐induced polarization (PHIP) is a technique capable of producing spin at magnitude far greater than state‐of‐the‐art magnets. A significant application PHIP to generate contrast agents for biomedical imaging. Clinically viable and effective not only require high levels but heterogeneous catalysts that can be used in water eliminate the toxicity impact. Herein, we demonstrate use Pt nanoparticles capped with glutathione induce water. The ligand‐inhibited surface...
Parahydrogen induced polarization (PHIP) is a hyperpolarization method for NMR signal enhancement with applications in spectroscopy and imaging. Although parahydrogen can be easily enriched up to nearly 95%, the detected on hydrogenated substrate substantially lower, where numerous loss mechanisms between start of hydrogenation reaction detection affect levels. The quality PHIP systems commonly determined by stating either degree or factor product at time detection. In this study, we present...
In a typical magic-angle spinning (MAS) dynamic nuclear polarization (DNP) magnetic resonance (NMR) experiment, several mechanisms are simultaneously involved when transferring much larger of electron spins to NMR active nuclei interest. Recently, specific cross-relaxation enhancement by motions under DNP (SCREAM-DNP) [Daube et al. JACS 2016] has been reported as one these mechanisms. Thereby 13C with inverted sign was observed in direct (DP) MAS caused reorientation dynamics methyl that not...
Hyperpolarization with parahydrogen (p-H2 ) is a fast developing field in NMR, which enables overcoming the inherent low sensitivity of this important technique. The hyperpolarization solvents, particularly water, offers wide range applications for structural investigations macromolecules and biomedical imaging. Until lately, only organic solvents could be polarized by means via coherent redistribution polarization (SABRE mechanism). In study, we investigate detail mechanism recently...
Abstract Enhancing lithium-ion battery technology in terms of specific capacity and charging time is key for the advancement electrification transportation. Particularly fast charging, inhomogeneous deposition metallic lithium, example on commercial graphite or lithium anodes, leads to cell degradation safety issues. To understand underlying mechanisms develop counter-measures, non-invasive online detection techniques providing satisfactory resolution are crucial. Here, we demonstrate...
In operando nuclear magnetic resonance (NMR) spectroscopy is one method for the online investigation of electrochemical systems and reactions. It allows real-time observations formation products intermediates, it grants insights into interactions substrates catalysts. An in NMR setup electrolytic reduction CO2 at silver electrodes has been developed. The electrolysis cell consists a three-electrode using working electrode pristine silver, chlorinated wire as reference electrode, graphite...
It is of general interest to combine the faradaic processes based high energy density a battery with non-faradaic power capacitor in one cell. Surface area and functional groups electrode materials strongly affect these properties. For anode material Li4Ti5O12 (LTO), we suggest polaron mechanism that influences Li ion uptake mobility. Here show electrolytes containing lithium salt induce an observable change bulk NMR relaxation properties LTO nano particles. The longitudinal 7Li time can by...
Hydrothermal carbon (HTC) derived from biomass is a class of cost-efficient, eco-friendly functional materials with various potential applications. In this work, solid-state nuclear magnetic resonance (NMR), longitudinal (T1) relaxation time, and diffusion NMR were employed to investigate the structure water dynamics for HTC nitrogen-functionalized hydrothermal (N-HTC) samples ((N)-HTC). Results showed that presence N-functional groups influences interaction (N)-HTC more strongly than...
Abstract Das mechanistische Verständnis der aktiven Zentren, adsorbierten Zwischenprodukte und geschwindigkeitsbestimmenden Schritte (RDS) von N‐modifizierten Kohlenstoffkatalysatoren in elektrokatalytischen Sauerstoffreduktion (ORR) Sauerstoffentwicklung (OER) ist wegen unvermeidlichen Koexistenz verschiedener N‐Konfigurationen technischen Beschränkungen bei Beobachtung gebildeter noch immer umstritten. Hier werden sieben Arten aromatischer Moleküle mit je einer einzelnen N‐Spezies als...
Abstract Battery fast charging is pivotal for broader acceptance of electric mobility. While demonstrated lithium titanate $$(\text {Li}_4\text {Ti}_5\text {O}_{12},$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>(</mml:mo> <mml:msub> <mml:mtext>Li</mml:mtext> <mml:mn>4</mml:mn> </mml:msub> <mml:mtext>Ti</mml:mtext> <mml:mn>5</mml:mn> <mml:mtext>O</mml:mtext> <mml:mn>12</mml:mn> <mml:mo>,</mml:mo> </mml:mrow> </mml:math> LTO) anodes, the underlying mechanisms...