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Inspired by the good performance of argyrodites as ion conducting thermoelectrics and as solid electrolytes we investigated the effect of isovalent S2− substitution for Se2− in Cu7PSe6.
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Research Interests: Materials Science, Nanoparticle, Crystallization, Nanotechnology, Polymers, and 15 moreMedicine, Multidisciplinary, Polymer, Magnetic nanoparticles, Nanostructures, Particle Size, Magnetic Nanoparticles, Molecular Conformation, Phosphoramidate, Materials Testing, Ferric Compounds, Nucleic Acid, Linker, maghemite, and Immunomagnetic separation
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Co-doped anatase and rutile bulk-samples prepared by the sol–gel technique are found to be paramagnetic at room-temperature. Only further annealing in Ar/H2 gas results in a ferromagnetic behavior. X-ray diffraction and... more
Co-doped anatase and rutile bulk-samples prepared by the sol–gel technique are found to be paramagnetic at room-temperature. Only further annealing in Ar/H2 gas results in a ferromagnetic behavior. X-ray diffraction and electron-microscope studies reveal for low doping levels <4% the formation of Co-doped rutile samples and the formation of CoTiO3 as a new phase. Co3O4 can be detected in anatase samples with Co doping levels ⩾4%. The observed Co oxides are reduced by Ar/H2 to Co metal. The room-temperature ferromagnetism can therefore be traced back to a segregation of metallic Co.
Research Interests: Materials Science, Inorganic Chemistry, Solid State Chemistry, Sample Preparation, Doping, and 15 moreSol Gel Process, Annealing, Magnetic Properties, Metal, Solubility, CO oxidation, Anatase, X ray diffraction, Room Temperature, Ambient Temperature, Titanium oxide, Ferromagnetism, Electron Microscope, Rutile, and Paramagnetism
ABSTRACT Herein, we present the electrochemical characterization of carbon-coated TiO2 nanorods, obtained by carbonizing RAFT (reversible addition fragmentation chain transfer) polymerization derived block copolymers anchored on anatase... more
ABSTRACT Herein, we present the electrochemical characterization of carbon-coated TiO2 nanorods, obtained by carbonizing RAFT (reversible addition fragmentation chain transfer) polymerization derived block copolymers anchored on anatase TiO2 nanorods. These carbon-coated TiO2 nanorods show an improved electrochemical performance in terms of first cycle reversibility, specific capacity, cycling stability, and high rate capability. More importantly, however, the structural disordering observed in the uncoated TiO2 nanorods by means of galvanostatic and potentiodynamic cycling as well as ex situ XRD analysis, does not occur for the carbon-coated material. Preventing this structural disordering does not only result in a stabilized cycling performance but, moreover, in substantially enhanced energy storage efficiency (86% vs. only 68% at the 100th cycle) due to the preserved characteristic potential profile of anatase TiO2.
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... Nicole Zink , Julien Pansiot , Jérôme Kieffer , Helen Annal Therese , Martin Panthöfer , Frank Rocker , Ute Kolb and Wolfgang Tremel* . Institut für Anorganische Chemie and Analytische Chemie, Johannes Gutenberg ...
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Nanostructures of varied dimensionality such as rods, scrolls, and disks of molybdenum oxide have been synthesized in gram quantities under ambient conditions using exfoliation of the layers as a synthetic tool. Intercalation of... more
Nanostructures of varied dimensionality such as rods, scrolls, and disks of molybdenum oxide have been synthesized in gram quantities under ambient conditions using exfoliation of the layers as a synthetic tool. Intercalation of alkylamines (C n H 2 n +2 NH 2 , where n = 3, 4, 8, 12, ...
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ABSTRACT The third dimension comes to the rescue in the synthesis of laterally confined 2D crystals. Graphene-type sheets of layered metal(IV) chalcogenides are stabilized by stacking to form nano-objects that resemble a coin roll.... more
ABSTRACT The third dimension comes to the rescue in the synthesis of laterally confined 2D crystals. Graphene-type sheets of layered metal(IV) chalcogenides are stabilized by stacking to form nano-objects that resemble a coin roll. Mismatch strain between NbS2 and WS2 lattices is important for the stabilization of the coin-roll structure as well as for preventing the formation of the intrinsically more stable scroll structures such as fullerenes or nanotubes.
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Page 1. Enzyme-Mediated Deposition of a TiO2 Coating onto Biofunctionalized WS2 Chalcogenide Nanotubes By Muhammad Nawaz Tahir, Filipe Natalio, Helen Annal Therese, Aswani Yella, Nadine Metz, Muhammad Raza Shah, Enrico Mugnaioli, ...
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A hitherto unknown phase of sodium titanate, NaTi3O6(OH)·2H2O, was identified as the intermediate species in the synthesis of TiO2 nanorods. This new phase, prepared as nanorods, was investigated by electron diffraction, X-ray powder... more
A hitherto unknown phase of sodium titanate, NaTi3O6(OH)·2H2O, was identified as the intermediate species in the synthesis of TiO2 nanorods. This new phase, prepared as nanorods, was investigated by electron diffraction, X-ray powder diffraction, thermogravimetric analysis and high-resolution transmission electron microscopy. The structure was determined ab initio using electron diffraction data collected by the recently developed automated diffraction tomography technique. NaTi3O6(OH)·2H2O crystallizes in the monoclinic space group C2/m. Corrugated layers of corner- and edge-sharing distorted TiO6 octahedra are intercalated with Na+ and water of crystallization. The nanorods are typically affected by pervasive defects, such as mutual layer shifts, that produce diffraction streaks along c*. In addition, edge dislocations were observed in HRTEM images.
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Monodisperse copper-iron-sulfide (CuFeS2) nanoparticles as the infrared light absorbing material (chalcopyrite, 0.65 eV), were synthesized based on facile, one step heating up method, by dissolving of CuCl, FeCl3 and SC(NH2)2 as... more
Monodisperse copper-iron-sulfide (CuFeS2) nanoparticles as the infrared light absorbing material (chalcopyrite, 0.65 eV), were synthesized based on facile, one step heating up method, by dissolving of CuCl, FeCl3 and SC(NH2)2 as precursors in oleylamine (OLA) alone or in combination with oleic acid (OA) and 1-octadecene (ODE) as solvent. The phase, size, morphology, and size distribution were controlled by the reaction conditions and temperature. The CuFeS2 nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectrum and ultraviolet-visible-near infrared. The three main absorbance region was observed in the ultraviolet, visible and infrared as a hybridization of Fe 3d-S 3p among the valence band (Cu 3d-S 3p) and conduction band (Cu 4s-Fe 4s). Well controlled CuFeS2 triangular pyramidal along with semi-hexagonal and hexagonal shape (~ 20-25 nm) was obtained by using OLA or a mixture of OLA along with OA and ...
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A facile and chemical specific method to synthesize highly reduced graphene oxide (HRG) and Pd (HRG@Pd) nanocomposite is presented. The HRG surfaces are tailored with amine groups using 1-aminopyrene (1-AP) as functionalizing molecules.... more
A facile and chemical specific method to synthesize highly reduced graphene oxide (HRG) and Pd (HRG@Pd) nanocomposite is presented. The HRG surfaces are tailored with amine groups using 1-aminopyrene (1-AP) as functionalizing molecules. The aromatic rings of 1-AP sit on the basal planes of HRG through π–π interactions, leaving amino groups outwards (similar like self-assembled monolayer on 2D substrates). The amino groups provide the chemically specific binding sites to the Pd nucleation which subsequently grow into nanoparticles. HRG@Pd nanocomposite demonstrated both uniform distribution of Pd nanoparticles on HRG surface as well as excellent physical stability and dispersibility. The surface functionalization was confirmed using, ultraviolet–visible (UV–Vis), Fourier transform infra-red and Raman spectroscopy. The size and distribution of Pd nanoparticles on the HRG and crystallinity were confirmed using high-resolution transmission electron microscopy and powder X-ray diffractio...
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ZrOx(1%)–MnCO3/HRG(1%) based nanocomposites material as an efficient oxidation catalyst.
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The Magnéli phase VO was synthesized in gram amounts from a powder mixture of VO/VO and vanadium metal, using the spark plasma sintering (SPS) technique. Its structure was determined with synchrotron X-ray powder diffraction data from a... more
The Magnéli phase VO was synthesized in gram amounts from a powder mixture of VO/VO and vanadium metal, using the spark plasma sintering (SPS) technique. Its structure was determined with synchrotron X-ray powder diffraction data from a phase-pure sample synthesized by conventional solid-state synthesis. A special feature of Magnéli-type oxides is a combination of crystallographic shear and intrinsic disorder that leads to relatively low lattice thermal conductivities. SPS prepared VO has a relatively low thermal conductivity of κ = 2.72 ± 0.06 W (m K) while being a n-type conductor with an electrical conductivity of σ = 0.039 ± 0.005 (μΩ m), a Seebeck coefficient of α = -(35 ± 2) μV K, which leads to a power factor of PF = 4.9 ± 0.8 × 10W (m K) at ∼600 K. Advances in the application of Magnéli phases are mostly hindered by synthetic and processing challenges, especially when metastable and nanostructured materials such as VO are involved. This study gives insight into the complicat...
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The transformation of amorphous precursors into crystalline solids and the associated mechanisms are still poorly understood. We illuminate the formation and reactivity of an amorphous cobalt phosphate hydrate precursor and the role of... more
The transformation of amorphous precursors into crystalline solids and the associated mechanisms are still poorly understood. We illuminate the formation and reactivity of an amorphous cobalt phosphate hydrate precursor and the role of water for its crystallization process. Amorphous cobalt phosphate hydrate nanoparticles (ACP) with diameters of ∼20 nm were prepared in the absence of additives from aqueous solutions at low concentrations and with short reaction times. To avoid the kinetically controlled transformation of metastable ACP into crystalline Co3(PO4)2 × 8 H2O (CPO) its separation must be fast. The crystallinity of ACP could be controlled through the temperature during precipitation. A second amorphous phase (HT-ACP) containing less water and anhydrous Co3(PO4)2 was formed at higher temperature by the release of coordinating water. ACP contains approximately five molecules of structural water per formula unit as determined by thermal analysis (TGA) and quantitative IR spectroscopy. The Co2+ coor...
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Recently, green reduction of graphene oxide (GRO) using various natural materials, including plant extracts, has drawn significant attention among the scientific community. These methods are sustainable, low cost, and are more... more
Recently, green reduction of graphene oxide (GRO) using various natural materials, including plant extracts, has drawn significant attention among the scientific community. These methods are sustainable, low cost, and are more environmentally friendly than other standard methods of reduction. Herein, we report a facile and eco-friendly method for the bioreduction of GRO using Salvadora persica L. (S. persica L.) roots (miswak) extract as a bioreductant. The as-prepared highly reduced graphene oxide (SP-HRG) was characterized using powder X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron (XPS) spectroscopy, and transmission electron microscopy (TEM). Various results have confirmed that the biomolecules present in the root extract of miswak not only act as a bioreductant but also functionalize the surface of SP-HRG by acting as a capping ligand to stabilize it in water and other ...
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Research Interests: Materials Science, Electron Diffraction, Confocal Microscopy, Polymers, Atomic Force Microscopy, and 15 moreMedicine, Biocompatibility, Humans, Nanotubes, Physical sciences, Nanorod, CHEMICAL SCIENCES, Hydrogen Peroxide, High Resolution, HeLa cells, Confocal Laser Scanning Microscopy, Aqueous Solution, Catalytic Activity, Hybrid System, and nanoscale
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Nanoparticular FeSb2 was prepared in solution from cyclopentadienyl iron(ii) dicarbonyl dimer [Fe(Cp(CO)2)]2 and antimony nanoparticles. Spark plasma sintering was used as consolidation method to maintain the particle size. The... more
Nanoparticular FeSb2 was prepared in solution from cyclopentadienyl iron(ii) dicarbonyl dimer [Fe(Cp(CO)2)]2 and antimony nanoparticles. Spark plasma sintering was used as consolidation method to maintain the particle size. The thermoelectric performance of FeSb2 is limited by its high thermal conductivity. In this work, the thermal conductivity was suppressed by nearly 80% compared to the bulk value by introducing grain boundary scattering of phonons on the nanoscale. The thermoelectric properties of the consolidated FeSb2 emphasize the possibility of altering thermal transport of promising thermoelectric compounds by phonon scattering by engineering the interfaces at the nanoscale.
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Although terminal chalcogeno ligands are well known for the group 5 and 6 transition metals, they are highly unusual for the oxophilic group 4 metals and unknown so far for the lanthanides or actinides. Cs3UP2S8, is the first actinide... more
Although terminal chalcogeno ligands are well known for the group 5 and 6 transition metals, they are highly unusual for the oxophilic group 4 metals and unknown so far for the lanthanides or actinides. Cs3UP2S8, is the first actinide compound containing a terminal M=S group. It was synthesized by reacting uranium metal, Cs2S, S, and P2S5 in a 4:1:8:3 ratio at 700 °C in an eutectic LiCl/CsCl mixture. The crystal structure was determined by single‐crystal X‐ray diffraction techniques. Cs3UP2S8 crystallizes in the rhombohedral space group R$\bar{3}$ [a = 15.5217(8) Å; c = 35.132(2) Å, V = 8305.0(8) Å3, Z = 18]. The crystal structure is based on a tetrahedral network type, wherein the uranium atoms are coordinated by a unusual sulfido moiety and thiophosphate groups in a pseudo‐tetrahedral fashion. The U=S distance of 2.635(3) Å observed in the sulfide moiety is approx. 0.2 Å shorter than the average U–S single bond length, indicating a double‐bond type character.