Finetuning hierarchical energy material microstructure via high temperature material synthesis route
Not Available
Mondal, K. (ORCID:0000000316657755)↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Driven Majorana modes: A route to synthetic $p_x +ip_y$ superconductivity
We propose a protocol to realize synthetic $p_x +ip_y$ superconductors in one-dimensional topological systems that host Majorana fermions. By periodically driving a localized Majorana mode across the system, our protocol realizes a topological pumping of Majorana fermions, analogous to the adiabatic Thouless pumping of electrical charges. Importantly, similar to the realization of a Chern insulator through Thouless pumping, we show that pumping of Majorana zero modes could lead to a $p_x +ip_y$ superconductor in the two dimensions of space and synthetic time. The Floquet theory is employed to map the driven one-dimensional system to a two-dimensional synthetic system by considering frequency as a new dimension. We demonstrate such Floquet $p_x +ip_y$ superconductors using the Kitaev $p$-wave superconductor chain, a prototypical 1D topological system, as well as its more realistic realization in the 1D Kondo lattice model as examples. We further show the appearance of Majorana $π$ mode at the Floquet zone boundary in an intermediate drive frequency region. Our work suggests a driven magnetic spiral coupled to a superconductor as a promising platform for the realization of novel topological superconductors.
36 MATERIALS SCIENCE↗
Defective Sn-Zn perovskites through bio-directed routes for modulating CO 2 RR
Sn and Zn oxides can catalyze electrochemical CO 2 reduction reactions (CO 2 RR) to produce useful chemicals. Herein, we report on perovskite-type tin-zinc oxides (TZO) synthesized by a biomineralization approach under benign aqueous conditions. The resulting TZO catalysts are disordered and possess a high quantity of defects, which serve as highly reactive active sites in CO 2 RR. Selectively toward formate or CO is tunable toward the relative amounts of Sn and Zn and their associated O defects. In-situ X-ray absorption spectroscopy measurements reveal electronic and structural transformations consistent with oxygen vacancy formation at Sn-O-Zn bridges as a function of cathodic potential that strongly correlates to CO2RR selectivity. Further, Density functional theory (DFT) calculations demonstrate that introducing an oxygen vacancy in TZO influences drastically influences formate/CO selectivity, consistent with our in-situ XAS findings and catalytic performance. Overall, these findings demonstrate the potential of biomineralization to fabricate perovskite-type metal oxides for energy conversion reactions.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Investigating the impact of preparation routes on the properties of copper-decorated silicon particles as anode materials for lithium-ion batteries
In recent years, the calendar life of Si has been recognized as a significant issue that must be addressed prior to technology deployment: The carbon conductive additive is a potential source of parasitic side reactions. However, carbon remains essential due to the low electronic conductivity of Si. In this study, we investigate the use of Cu as a conductive additive and potential alternative to carbon. Some Cu-decorated silicon particles (Si Cu ) were prepared using physical vapor deposition (PVD) via sputtering and high-energy milling. Other Si Cu particles were prepared by using a solution method and examined briefly. The milling method caused Cu to appear as island-like features on the Si surface, whereas the PVD method initially produced similar island-like features that gradually developed into a continuous coating around the Si as sputtering time increased. Electrodes fabricated from Si Cu exhibited lower overall resistivity, demonstrating the beneficial effect of Cu in improving electronic percolation through the electrode. Electrochemical tests showed that the milled SiCu exhibited higher capacity retention, improved rate capability, and lower overpotential. Furthermore, Si Cu coupled with an NMC811 cathode exhibited lower leakage currents compared with the baseline silicon, indicating that incorporating Cu provided an additional advantage of minimizing parasitic currents in the cells.
25 ENERGY STORAGE↗
Plasmonic Ag nanocomposite phosphate glasses produced via γ-ray irradiation as reduction route
This paper reports on the impact of γ-ray irradiation (10, 100 kGy) on melt-quenched Ag + -doped phosphate glass and the effects of subsequent thermal processing leading to the production of plasmonic Ag nanocomposites. The γ-irradiated glasses were characterized alongside the pristine by differential scanning calorimetry (DSC), Raman spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, optical absorption, and photoluminescence (PL) spectroscopy. DSC characterization showed consistent glass transition temperatures (T g ) before and after γ-irradiation whereas the crystallization temperatures tended to decrease with increasing γ-ray dose. However, a lack of alteration of the glass network structure was supported by Raman spectroscopy. Room temperature EPR spectra clearly showed the formation of phosphorus oxygen hole center (POHC) defects in the undoped host, in addition to another doublet likely associated with a P 3 defect. The presence of paramagnetic silver species encompassing Ag 2+ and 107/109 Ag 0 atoms was also indicated in the silver-activated glass together with POHC defects. Optical absorption spectra were also consistent with the presence of various radiation-induced centers. Further analyzing the glass absorption edge via Tauc plots suggested the formation of electron center (EC) defects in γ-irradiated samples wherein the silver-doped glass exhibited decreasing band gap energies with increasing γ-ray dose. The PL characterization showed the silver-related radio-PL effect was induced exhibiting broad band emission with two maxima around 500 and 625 nm stemming from various molecular Ag$^{x+}_{n}$ clusters. Emission decay analyses revealed that the longer wavelength emission exhibited slower decay. The highest radiation dose of 100 kGy however resulted in weaker emission and faster decay kinetics attributed to energy transfer between the luminescent silver species and POHC defects. Finally subjecting the γ-irradiated Ag-doped glasses to heat treatment near the T g at 490 °C led to the development of the surface plasmon resonance of Ag nanoparticles (NPs) and the vanishing of the Ag$^{x+}_{n}$ clusters luminescence. In conclusion, the presence of the matrix-related EC defects was deemed accountable for the thermally induced reduction and consequent precipitation of Ag NPs making the plasmonic glasses attractive for photonic applications such as nonlinear optics.
36 MATERIALS SCIENCE↗
Route of exposure influences pesticide body burden and the hepatic metabolome in post-metamorphic leopard frogs
Not Available
Glinski, Donna A.↗
A facile route towards large area self-assembled nanoscale silver film morphologies and their applications towards metal enhanced fluorescence
Here, we present a facile method for fabricating nanostructured silver films containing a high density of nanoscopic gap features through a surface directed phenomenon utilizing nanoporous scaffolds rather than through traditional lithographic patterning processes. This method enables tunability of the silver film growth by simply adjusting the formulation and processing conditions of the nanoporous film prior to metallization. We further demonstrate that this process can produce nanoscopic gaps in thick (100 nm) silver films supporting localized surface plasmon resonance with large field amplification within the gaps while enabling launching of propagating surface plasmons within the silver grains. These enhanced fields provide metal enhanced fluorescence with enhancement factors as high as 21 times compared to glass, as well as enable visualization of single fluorophore emission. This work provides a low-cost rapid approach for producing novel nanostructures capable of broadband fluorescence amplification, with potential applications including plasmonic and fluorescence based optical sensing and imaging applications.
36 MATERIALS SCIENCE↗
Recovery of zinc and cadmium from spent batteries using Cyphos IL 102 via solvent extraction route and synthesis of Zn and Cd oxide nanoparticles
Highlights: • First time Cyphos IL102 explored for recovery of Zn/Cd from spent batteries. • Recovery of metals with high purity was achieved at room temperature. • Quantitative extraction was achieved in two stages for Zn and Cd. •Loaded organic phases were used to synthesize ZnO and CdO nanoparticles. •Simple strippants for stripping isotherm was used. - Abstract: The overall aim of this study is to separate and recover zinc and cadmium from spent batteries. For this purpose Cyphos IL 102 diluted in toluene was employed for the extraction and recovery of Zn and Cd from Zn-C and Ni-Cd batteries leach liquor. The influence of extractant concentration for the leach liquors of Zn-C (0.01–0.05 mol/L) and Ni-Cd (0.04–0.20 mol/L) batteries has been investigated. Composition of the leach liquor obtained from Zn-C/Ni-Cd spent batteries is Zn - 2.18 g/L, Mn - 4.59 g/L, Fe - 4.0 × 10{sup −3} g/L, Ni - 0.2 × 10{sup −3} g/L/Cd - 4.28 g/L, Ni - 0.896 × 10{sup −1} g/L, Fe - 0.148 g/L, Co - 3.77 × 10{sup −3} g/L, respectively. Two stage counter current extraction at A/O 1:1 and 3:2 with 0.04 mol/L and 0.2 mol/L Cyphos IL 102 for Zn and Cd, respectively provide more than 99.0% extraction of both the metal ions with almost negligible extraction of associated metal ions. A stripping efficiency of around 99.0% for Zn and Cd was obtained at O/A 1:1 using 1.0 mol/L HNO{sub 3} in two and three counter current stages, respectively. ZnO and CdO were also synthesized using the loaded organic phase and characterized using XRD, FE-SEM and EDX techniques. XRD peaks of ZnO and CdO correspond to zincite and monteponite, respectively. The average particle size was ∼27.0 nm and ∼37.0 nm for ZnO and CdO, respectively. The EDX analysis of ZnO and CdO shows almost 1:1 atomic percentage.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Mitochondrial DNA disease—molecular insights and potential routes to a cure
Mitochondrial DNA diseases are common neurological conditions caused by mutations in the mitochondrial genome or nuclear genes responsible for its maintenance. Current treatments for these disorders are focussed on the management of the symptoms, rather than the correction of biochemical defects caused by the mutation. This review focuses on the molecular effects of mutations, the symptoms they cause and current work focusing on the development of targeted treatments for mitochondrial DNA disease. - Highlights: • We discuss several common disease causing mtDNA mutations. • We highlight recent work linking pathogenicity to deletion size and heteroplasmy. • We discuss recent advances in the development of targeted mtDNA disease treatments.
60 APPLIED LIFE SCIENCES↗
Lanthanide Complexes of Bis(tetrazolato)amine: A Route to Lanthanide Nitride Foams
Not Available
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Single-crystal-to-single-crystal metalation of a metal-organic framework: A route toward structurally well-defined catalysts
Metal–organic frameworks featuring ligands with open chelating groups are versatile platforms for the preparation of a diverse set of heterogeneous catalysts through postsynthetic metalation. The crystalline nature of these materials allows them to be characterized via X-ray diffraction, which provides valuable insight into the structure of the metal sites that facilitate catalysis. A highly porous and thermally robust zirconium-based metal–organic framework, Zr 6 O 4 (OH) 4 (bpydc) 6 (bpydc 2– = 2,2'-bipyridne-5,5'-dicarboxylate), bears open bipyridine sites that readily react with a variety of solution- and gas-phase metal sources to form the corresponding metalated frameworks. Remarkably, Zr 6 O 4 (OH) 4 (bpydc) 6 undergoes a single-crystal-to-single-crystal transformation upon metalation that involves a change in space group from $Fm\bar{3}m$ to $Pa\bar{3}m$. This structural transformation leads to an ordering of the metalated linkers within the framework, allowing structural characterization of the resulting metal complexes. Furthermore, Zr 6 O 4 (OH) 4 (bpydc) 6 yields an active heterogeneous catalyst for arene C–H borylation when metalated with [Ir(COD) 2 ]BF 4 (COD = 1,5-cyclooctadiene). These results highlight the unique potential of metal–organic frameworks as a class of heterogeneous catalysts that allow unparalleled structural characterization and control over their active sites.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗