Refine
Has Fulltext
- no (77)
Year of publication
- 2022 (77) (remove)
Document Type
- Article (77) (remove)
Is part of the Bibliography
- yes (77)
Keywords
- electrochemistry (3)
- liposomes (2)
- lithium-sulfur batteries (2)
- 3D-printing (1)
- 4-nitrophenol (1)
- 4D-actuation (1)
- Adsorption (1)
- Ageing (1)
- Aldehydes (1)
- Anodes (1)
- Arabica coffee (1)
- Aromaticity (1)
- Au-Pd nanorods (1)
- Ball milling (1)
- BeWo b30 (1)
- CO 2 reduction reaction (1)
- Catalysts (1)
- Charge transfer (1)
- Chemical dynamics (1)
- Cluster chemistry (1)
- Coherent states (1)
- Cyclazines (1)
- DFT (1)
- Degradable (1)
- Density-matrix (1)
- Distance Learning (1)
- Dual-Responsiveness (1)
- Electrochemical impedance (1)
- Elektrolumineszenz (1)
- Excited-state calculations; (1)
- Experiment (1)
- Fastener (1)
- Fiber-optical spectroscopy (1)
- Formic acid (1)
- Functional groups (1)
- Games; (1)
- Gas phase (1)
- Gel polymer (1)
- Graphene derivates (1)
- Graphene oxide (1)
- Gripper (1)
- Halbleiter (1)
- Halogenation (1)
- Hard carbons (1)
- Hofmeister effect (1)
- Humor (1)
- Hydrocarbons (1)
- Ink (1)
- Interfacial capacitance (1)
- Internet (1)
- Ion exchange (1)
- Ionic conductivity (1)
- Ionic selectivity (1)
- Ki67 (1)
- LC-MS/MS (1)
- Lanthanides (1)
- Li-S (1)
- Manipulation of Emulsion Stability (1)
- Markov processes (1)
- Mesh ultra-thin layer (1)
- Metathesis (1)
- Microporosity (1)
- Mixtures (1)
- Modeling (1)
- Molecular (1)
- Molecular weight (1)
- Multiple light scattering (1)
- N-butylpyridinium bromide (1)
- NMR spectroscopy (1)
- Near infra-red (1)
- Ni-O4 electrocatalysts (1)
- Ni2F5 (1)
- Noble carbon (1)
- Novozym 435 (1)
- Open quantum systems (1)
- Organic Chemistry (1)
- Oxidation (1)
- PDA (1)
- Packaging (1)
- Peripheral ring current (1)
- Photon density wave spectroscopy (1)
- Polymer (1)
- Porous (1)
- Process (1)
- Protein (1)
- Puzzles (1)
- Reaction products (1)
- Reagents (1)
- SERS (1)
- SPR (1)
- Second-Year Undergraduate (1)
- Self Instruction (1)
- Simulation (1)
- Sodium-ion batteries (1)
- Spiropyrane (1)
- Surface science (1)
- Surfactant (1)
- Switchable Surfactants (1)
- TD-DFT (1)
- TE interactions (1)
- Thiouracil (1)
- Ti4O7 (1)
- Time-resolved spectroscopy (1)
- UV-VIS Spectroscopy (1)
- Ultra-low (1)
- Upconversion luminescence (1)
- Uracil (1)
- Vibrational states (1)
- Web-Based Learning (1)
- X-ray diffraction (1)
- active scaffold (1)
- addition-fragmentation chain-transfer polymerization (1)
- analytical technology (1)
- antimicrobial polymers (1)
- batteries (1)
- beta-galactosidase (1)
- bioinstructive materials (1)
- biomaterial (1)
- bottlebrush copolymers (1)
- bottom-up fabrication (1)
- bound phenolic compounds (1)
- cardiac regeneration (1)
- cell cycle inhibitors (1)
- ceria (1)
- chemical interface damping (1)
- coffee processing (1)
- colloidal quantum dots (1)
- critical micellation temperature (1)
- crystal structure prediction (1)
- crystals (1)
- curriculare Innovation (1)
- curriculum innovation (1)
- cytidine (1)
- degradable (1)
- electrical resistivity tomography (1)
- electroluminescence (1)
- energy storage (1)
- enzymatic sensors (1)
- experiment (1)
- fiber optic sensors (1)
- fiber sensors (1)
- fluorescence (1)
- function by structure; (1)
- functional (1)
- glycopolymers (1)
- hollow nanospheres (1)
- hydrate formation (1)
- hydration layer (1)
- hydrogel (1)
- immunosensors (1)
- incomplete surface passivation (1)
- indium (1)
- interactions (1)
- interferometry (1)
- inverse (1)
- ionic liquid crystals (1)
- ionic liquids (1)
- iron (1)
- iron nitride (1)
- layer-by-layer self-assembly (1)
- layer-by-layer stacking (1)
- life cycle assessment (1)
- ligands (1)
- light (1)
- lithium-sulfur battery (1)
- manganese (1)
- manganese monoxide (1)
- membrane (1)
- mesogen mesophases (1)
- metal-containing ionic liquids; (1)
- methane hydrate (1)
- microgel arrays (1)
- microwave irradiation (1)
- modulation of in vivo regeneration (1)
- molecular imprinted polymers (1)
- molecules (1)
- monomer (1)
- multifunctional biomaterials (1)
- multilayer film (1)
- nanocomposite (1)
- nanovesicles (1)
- numerical simulation (1)
- on demand particle release (1)
- operando (1)
- optical (1)
- organosulfur (1)
- oxygen (1)
- p16 (1)
- p21 (1)
- pH-Dependent Photoresponsivity (1)
- peptide biomarkers (1)
- phonons (1)
- phosphide (1)
- photo-iniferter reversible addition-fragmentation chain-transfer (1)
- photo-mediated polymerization (1)
- photobioreactor (1)
- photothermal conversion (1)
- placental transfer (1)
- plasmonic chemistry (1)
- plasmonic nanohole arrays (1)
- platelet-rich plasma (1)
- poly(ionic liquid)s (1)
- polyelectrolyte (1)
- polyelectrolyte brushes (1)
- polymer (1)
- polymer surface (1)
- population doubling time (1)
- pouch cell (1)
- protein modification (1)
- pyrochlore (1)
- quartz crystal microbalance (1)
- radical polymerization (1)
- renewable (1)
- reversible (1)
- self-assembly (1)
- semiconductor (1)
- senescence-associated (1)
- shape-memory effect (1)
- smart materials (1)
- specific ion effects (1)
- sperical (1)
- spherical polyelectrolyte brushes (SPB) (1)
- storage capacity (1)
- studies (1)
- sulfur host (1)
- supported catalyst (1)
- surface chemistry (1)
- surface plasmon (1)
- surface-enhanced Raman scattering (1)
- sustainability (1)
- synthesis (1)
- temperature (1)
- temperature sensor (1)
- temperature-memory effect (1)
- tetrahalidometallates (1)
- thermosensitive (1)
- thiol passivation (1)
- transition metals (1)
- trophoblasts (1)
- zirconia (1)
Institute
- Institut für Chemie (77) (remove)
Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy
(2022)
Imaging the charge flow in photoexcited molecules would provide key information on photophysical and photochemical processes. Here the authors demonstrate tracking in real time after photoexcitation the change in charge density at a specific site of 2-thiouracil using time-resolved X-ray photoelectron spectroscopy. The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220-250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states.
Herein, the concept of constructing binder- and carbon additive-free organosulfur cathode was proved based on thiol-containing conducting polymer poly(4-(thiophene-3-yl) benzenethiol) (PTBT). The PTBT featured the polythiophene-structure main chain as a highly conducting framework and the benzenethiol side chain to copolymerize with sulfur and form a crosslinked organosulfur polymer (namely S/PTBT). Meanwhile, it could be in-situ deposited on the current collector by electro-polymerization, making it a binder-free and free-standing cathode for Li-S batteries. The S/PTBT cathode exhibited a reversible capacity of around 870 mAh g(-1) at 0.1 C and improved cycling performance compared to the physically mixed cathode (namely S&PTBT). This multifunction cathode eliminated the influence of the additives (carbon/binder), making it suitable to be applied as a model electrode for operando analysis. Operando X-ray imaging revealed the remarkable effect in the suppression of polysulfides shuttle via introducing covalent bonds, paving the way for the study of the intrinsic mechanisms in Li-S batteries.
Recent advances in organic solar cell performance have been mainly driven forward by combining high-performance p-type donor-acceptor copolymers (e.g.PM6) and non-fullerene small molecule acceptors (e.g.Y6) as bulk-heterojunction layers. A general observation in such devices is that the device performance, e.g., the open-circuit voltage, is strongly dependent on the processing solvent. While the morphology is a typically named key parameter, the energetics of donor-acceptor blends are equally important, but less straightforward to access in the active multicomponent layer. Here, we propose to use spectral onsets during electrochemical cycling in a systematic spectroelectrochemical study of blend films to access the redox behavior and the frontier orbital energy levels of the individual compounds. Our study reveals that the highest occupied molecular orbital offset (Delta E-HOMO) in PM6:Y6 blends is similar to 0.3 eV, which is comparable to the binding energy of Y6 excitons and therefore implies a nearly zero driving force for the dissociation of Y6 excitons. Switching the PM6 orientation in the blend films from face-on to edge-on in bulk has only a minor influence on the positions of the energy levels, but shows significant differences in the open circuit voltage of the device. We explain this phenomenon by the different interfacial molecular orientations, which are known to affect the non-radiative decay rate of the charge-transfer state. We compare our results to ultraviolet photoelectron spectroscopy data, which shows distinct differences in the HOMO offsets in the PM6:Y6 blend compared to neat films. This highlights the necessity to measure the energy levels of the individual compounds in device-relevant blend films.
Plasmon-driven dehalogenation of brominated purines has been recently explored as a model system to understand fundamental aspects of plasmon-assisted chemical reactions. Here, it is shown that divalent Ca2+ ions strongly bridge the adsorption of bromoadenine (Br-Ade) to Ag surfaces.
Such ion-mediated binding increases the molecule's adsorption energy leading to an overlap of the metal energy states and the molecular states, enabling the chemical interface damping (CID) of the plasmon modes of the Ag nanostructures (i.e., direct electron transfer from the metal to Br-Ade).
Consequently, the conversion of Br-Ade to adenine almost doubles following the addition of Ca2+.
These experimental results, supported by theoretical calculations of the local density of states of the Ag/Br-Ade complex, indicate a change of the charge transfer pathway driving the dehalogenation reaction, from Landau damping (in the lack of Ca2+ ions) to CID (after the addition of Ca2+).
The results show that the surface dynamics of chemical species (including water molecules) play an essential role in charge transfer at plasmonic interfaces and cannot be ignored. It is envisioned that these results will help in designing more efficient nanoreactors, harnessing the full potential of plasmon-assisted chemistry.
Manganese (Mn) as well as iron (Fe) are essential trace elements (TE) important for the maintenance of physiological functions including fetal development. However, in the case of Mn, evidence suggests that excess levels of intrauterine Mn are associated with adverse pregnancy outcomes. Although Mn is known to cross the placenta, the fundamentals of Mn transfer kinetics and mechanisms are largely unknown. Moreover, exposure to combinations of TEs should be considered in mechanistic transfer studies, in particular for TEs expected to share similar transfer pathways. Here, we performed a mechanistic in vitro study on the placental transfer of Mn across a BeWo b30 trophoblast layer. Our data revealed distinct differences in the placental transfer of Mn and Fe. While placental permeability to Fe showed a clear inverse dose-dependency, Mn transfer was largely independent of the applied doses. Concurrent exposure of Mn and Fe revealed transfer interactions of Fe and Mn, indicating that they share common transfer mechanisms. In general, mRNA and protein expression of discussed transporters like DMT1, TfR, or FPN were only marginally altered in BeWo cells despite the different exposure scenarios highlighting that Mn transfer across the trophoblast layer likely involves a combination of active and passive transport processes.
Numerous phosphorus-rich metal phosphides containing both P-P bonds and metal-P bonds are known from the solid-state chemistry literature. A method to grow these materials in thin-film form would be desirable, as thin films are required in many applications and they are an ideal platform for high-throughput studies. In addition, the high density and smooth surfaces achievable in thin films are a significant advantage for characterization of transport and optical properties. Despite these benefits, there is hardly any published work on even the simplest binary phosphorus-rich phosphide films. Here, we demonstrate growth of single-phase CuP2 films by a two-step process involving reactive sputtering of amorphous CuP2+x and rapid annealing in an inert atmosphere. At the crystallization temperature, CuP2 is thermodynamically unstable with respect to Cu3P and P-4. However, CuP2 can be stabilized if the amorphous precursors are mixed on the atomic scale and are sufficiently close to the desired composition (neither too P poor nor too P rich). Fast formation of polycrystalline CuP2, combined with a short annealing time, makes it possible to bypass the diffusion processes responsible for decomposition. We find that thin-film CuP2 is a 1.5 eV band gap semiconductor with interesting properties, such as a high optical absorption coefficient (above 10(5) cm(-1)), low thermal conductivity (1.1 W/(K m)), and composition-insensitive electrical conductivity (around 1 S/cm). We anticipate that our processing route can be extended to other phosphorus-rich phosphides that are still awaiting thin-film synthesis and will lead to a more complete understanding of these materials and of their potential applications.
Guidance of postinfarct myocardial remodeling processes by an epicardial patch system may alleviate the consequences of ischemic heart disease. As macrophages are highly relevant in balancing immune response and regenerative processes their suitable instruction would ensure therapeutic success. A polymeric mesh capable of attracting and instructing monocytes by purely physical cues and accelerating implant degradation at the cell/implant interface is designed. In a murine model for myocardial infarction the meshes are compared to those either coated with extracellular matrix or loaded with induced cardiomyocyte progenitor cells. All implants promote macrophage infiltration and polarization in the epicardium, which is verified by in vitro experiments. 6 weeks post-MI, especially the implantation of the mesh attenuates left ventricular adverse remodeling processes as shown by reduced infarct size (14.7% vs 28-32%) and increased wall thickness (854 mu m vs 400-600 mu m), enhanced angiogenesis/arteriogenesis (more than 50% increase compared to controls and other groups), and improved heart function (ejection fraction = 36.8% compared to 12.7-31.3%). Upscaling as well as process controls is comprehensively considered in the presented mesh fabrication scheme to warrant further progression from bench to bedside.
Applications of advanced cathode materials with well-designed chemical components and/or optimized nanostructures promoting the sulfur redox kinetics and suppressing the shuttle effect of polysulfides are highly valued. However, in the case of actual lithium-sulfur (Li-S) batteries under practical working conditions, one long-term obstacle still exists, which is mainly due to the difficulties in massive synthesis of such nanomaterials with low cost and ease of control on the nanostructure. Herein, we develop a facile synthesis of carbon coated Ti4O7 hollow nanoparticles (Ti4O7) using spherical polymer electrolyte brush as soft template, which is scalable via utilizing a minipilot reactor. The C Ti4O7 hollow nanoparticles provide strong chemical adsorption to polysulfides through the large polar surface and additional physical confinement by rich micro- & mesopores and have successfully been employed as an efficient sulfur host for multilayer pouch cells. Besides, the sluggish kinetics of the sulfur and lithium sulfide redox mechanism can be improved by the highly conductive Ti4O7 via catalyzation of the conversion of polysulfides. Consequently, the C-Ti4O7 based pouch cell endows a high discharge capacity of 1003 mAhg(-1) at 0.05 C, a high-capacity retention of 83.7% after 100 cycles at 0.1 C, and a high Coulombic efficiency of 97.5% at the 100th cycle. This work proposes an effective approach to transfer the synthesis of hollow Ti4O7 nanoparticles from lab- to large-scale production, paving the way to explore a wide range of advanced nanomaterials for multilayer Li-S pouch cells.
Electrochemical reduction stands as an alternative to revalorize CO2. Among the different alternatives, Ni single atoms supported on carbonaceous materials are an appealing catalytic solution due to the low cost and versatility of the support and the optimal usage of Ni and its predicted selectivity and efficiency (ca. 100% towards CO). Herein, we have used noble carbonaceous support derived from cytosine to load Ni subnanometric sites. The large heteroatom content of the support allows the stabilization of up to 11 wt% of Ni without the formation of nanoparticles through a simple impregnation plus calcination approach, where nickel promotes the stabilization of C3NOx frameworks and the oxidative support promotes a high oxidation state of nickel. EXAFS analysis points at nickel single atoms or subnanometric clusters coordinated by oxygen in the material surface. Unlike the wellknown N-coordinated Ni single sites selectivity towards CO2 reduction, O-coordinated-Ni single sites (ca. 7 wt% of Ni) reduced CO2 to CO, but subnanometric clusters (11 wt% of Ni) foster the unprecedented formation of HCOOH with 27% Faradaic efficiency at - 1.4 V. Larger Ni amounts ended up on the formation of NiO nanoparticles and almost 100% selectivity towards hydrogen evolution.
Colloidal metal sulfide nanoparticles for high performance electrochemical energy storage systems
(2022)
Transition metal sulfides have emerged as excellent replacement candidates of traditional insertion electrode materials based on their conversion or alloying mechanisms, facilitating high specific capacity and rate ability. However, parasitic reactions such as massive volume change during the discharge/ charge processes, intermediate polysulfide dissolution, and passivating solid electrolyte interface formation have led to poor cyclability, hindering their feasibility and applicability in energy storage systems. Colloidal metal sulfide nanoparticles, a special class that integrates the intrinsic chemical properties of metal sulfides and their specified structural features, have fairly enlarged their contribution due to the synergistic effect. This review highlights the latest synthetic approaches based on colloidal process. Their corresponding electrochemical outcomes will also be discussed, which are thoroughly updated along with their insight scientific standpoints.