Controlled Molecular Arrangement of Cinnamic Acid in Layered Double Hydroxide through pi-pi Interaction for Controlled Release.

Cinnamic acid (CA) was successfully incorporated into Zn-Al layered double hydroxide (LDH) through coprecipitation. The CA moiety was stabilized in the interlayer space through not only electrostatic interaction but also intermolecular π-π interaction. It was noteworthy that the CA arrangement was fairly independent of the charge density of LDH, showing the important role of the layer-CA and CA-CA interactions in molecular stabilization.

Hybridization of Layered Titanium Oxides and Covalent Organic Nanosheets into Hollow Spheres for High-Performance Sodium-Ion Batteries with Boosted Electrical/Ionic Conductivity and Ultralong Cycle Life.

While development of a sodium-ion battery (SIB) cathode has been approached by various routes, research on compatible anodes for advanced SIB systems has not been sufficiently addressed. The anode materials based on titanium oxide typically show low electrical performances in SIB systems primarily due to their low electrical/ionic conductivity. Thus, in this work, layered titanium oxides were hybridized with covalent organic nanosheets (CONs), which exhibited excellent electrical conductivity, to be used as anodes in SIBs.

Exfoliation and Reassembly Routes to a Ge/RuO Nanocomposite as an Anode for Advanced Lithium-Ion Batteries.

Ge/RuO nanocomposites were successfully fabricated as anode materials for lithium-ion batteries using RuO nanosheets and Ge/GeO nanoparticles (NPs). X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) analyses showed that elemental Ge nanoparticles were distributed onto the rutile-type RuO. Transmission electron microscopy images showed well-dispersed Ge nanoparticles embedded in rutile-type RuO.

Microwave-Assisted Synthesis of Reduced Graphene Oxide with Hollow Nanostructure for Application to Lithium-Ion Batteries.

In this study, reduced graphene oxide (RGO) with a hollow nanostructure was successfully synthesized by layer-by-layer self-assembly using electrostatic interactions and van der Waals forces between building blocks, and its lithium storage characteristics were investigated. After 800 cycles at a current density of 1 A/g, the microwave-irradiated RGO hollow spheres (MRGO-HS) maintained a capacity of 626 mA h/g. In addition, when the charge/discharge capacity was measured stepwise in the current density range of 0.

Two-Dimensional Organic/Inorganic Hybrid Nanosheet Electrodes for Enhanced Electrical Conductivity toward Stable and High-Performance Sodium-Ion Batteries.

Invited for this month's cover are the groups of Jae-Min Oh, Jin Kuen Park, and Seung-Min Paek at three different universities in South Korea. The image shows how the supramolecular interaction between two different two-dimensional materials can control the electrical storage properties for a sodium-ion battery. The Full Paper itself is available at 10.

Two-Dimensional Organic/Inorganic Hybrid Nanosheet Electrodes for Enhanced Electrical Conductivity toward Stable and High-Performance Sodium-Ion Batteries.

To investigate the effect of electrical conductivity on the energy-storage characteristics of anode materials in sodium-ion batteries, covalent organic nanosheets (CONs) are hybridized with highly conductive graphene nanosheets (GNs) via two different optimized synthesis routes, that is, reflux and solvothermal methods. The reflux-synthesized hybrid shows a well-overlapped 2D structure, whereas the solvothermally prepared hybrid forms a segregated phase in which the contact area between the CONs and GNs is reduced. These two hybrids synthesized by facile methods are fully characterized, and the results reveal that their energy-storage properties can be significantly improved by enhancing the electrical conductivity via the formation of a well-overlapped structure between CONs and GNs.

Controlled Growth of Silver Oxide Nanoparticles on the Surface of Citrate Anion Intercalated Layered Double Hydroxide.

Silver oxide nanoparticles with controlled particle size were successfully obtained utilizing citrate-intercalated layered double hydroxide (LDH) as a substrate and Ag as a precursor. The lattice of LDH was partially dissolved during the reaction by Ag. The released hydroxyl and citrate acted as a reactant in crystal growth and a size controlling capping agent, respectively.

Porous Hybrids Structure between Silver Nanoparticle and Layered Double Hydroxide for Surface-Enhanced Raman Spectroscopy.

Silver nanoparticle (AgNP), in terms of antibacterial, catalytic, electronic, and optical applications, is an attractive material. Especially, when prepared to furnish sharp edge and systematic particle orientation on the substrate, AgNPs can take advantage of surface-enhanced Raman spectroscopy (SERS). In this research, we suggested a synthetic method to immobilize the AgNP on metal oxide by utilizing Ag-thiolate and layered double hydroxide (LDH) as precursor and template, respectively.

Microwave-Assisted Synthesis of Ge/GeO-Reduced Graphene Oxide Nanocomposite with Enhanced Discharge Capacity for Lithium-Ion Batteries.

Germanium/germanium oxide nanoparticles with theoretically high discharge capacities of 1624 and 2152 mAh/g have attracted significant research interest for their potential application as anode materials in Li-ion batteries. However, these materials exhibit poor long-term performance due to the large volume change of 370% during charge/discharge cycles. In the present study, to overcome this shortcoming, a Ge/GeO/graphene composite material was synthesized.

Formation mechanism of an Al Keggin cluster in hydrated layered polysilicates.

An Al13 ε-Keggin cluster, AlO4Al12(OH)24(H2O)127+, is a predominant intermediate during the hydrolysis and polymerization of aluminum as well as a highly toxic substance to plants and fishes. However, no one could clearly explain why and how a cage-like Al13 ε-Keggin cluster is formed even though it could be readily synthesized by the forced hydrolysis of Al3+. We found that the Al13 ε-Keggin cluster was spontaneously formed not in monocrystalline octosilicate but in polycrystalline magadiite by the cation-exchange reaction with unhydrolyzed Al3+.

Facile Synthetic Route To Prepare Ultrathin Silver Nanosheets by Reducing Silver Thiolates in Interlayer Surface of Layered Double Hydroxides.

Silver metal nanostructures have gained much interest, due to their utility in various fields, based on their unique properties at nanosize. Tremendous research efforts have been made to establish synthetic methods to manipulate their shape and size. The most challenging synthesis in silver nanostructures has been known as a plate-like shape having a few nanometers size thickness and high aspect ratio.

Theoretical and Experimental Understanding of Hydrogen Evolution Reaction Kinetics in Alkaline Electrolytes with Pt-Based Core-Shell Nanocrystals.

The free energy of H adsorption () on a metallic catalyst has been taken as a descriptor to predict the hydrogen evolution reaction (HER) kinetics but has not been well applied in alkaline media. To assess this, we prepare Pd@Pt and PdH@Pt core-shell octahedra enclosed by Pt(111) facets as model catalysts for controlling the affected by the ligand, the strain, and their ensemble effects. The Pt shell thickness is adjusted from 1 to 5 atomic layers by varying the amount of Pt precursor added during synthesis.

Covalent Organic Nanosheets as Effective Sodium-Ion Storage Materials.

Herein, we study the structure-dependent energy storage performance of network polymers (covalent organic nanosheets, CONs) prepared by Stille cross-coupling under conventional reflux and solvothermal conditions, showing that the specific surface area and self-assembled morphology of CONs could be effectively controlled by a careful choice of the synthetic route and monomer combination. The Na-ion storage capacity of the above nanosheets could be increased by enhancing their charge-carrier conductivity via enforcement of polymer backbone planarity or by increasing their specific surface area while maintaining backbone constitution. Comparison of anodes fabricated using six CONs showed that the electrode based on CON-16 exhibited the best cycling performance and rate capability, retaining a reversible discharge capacity of ∼250 mA h/g after 30 cycles at a current density of 100 mA/g.

Physico-chemical changes of ZnO nanoparticles with different size and surface chemistry under physiological pH conditions.

We studied the physico-chemical properties of ZnO nanoparticles under physiological pH conditions (gastric, intestinal and plasma) as functions of their size (20 and 70 nm) and surface chemistry (pristine, L-serine, or citrate coating). ZnO nanoparticles were dispersed in phosphate buffered saline under physiological pH conditions and aliquots were collected at specific time points (0.5, 1, 4, 10 and 24 h) for further characterization.

Physicochemical properties of surface charge-modified ZnO nanoparticles with different particle sizes.

In this study, four types of standardized ZnO nanoparticles were prepared for assessment of their potential biological risk. Powder-phased ZnO nanoparticles with different particle sizes (20 nm and 100 nm) were coated with citrate or L-serine to induce a negative or positive surface charge, respectively. The four types of coated ZnO nanoparticles were subjected to physicochemical evaluation according to the guidelines published by the Organisation for Economic Cooperation and Development.

Surface treatment of silica nanoparticles for stable and charge-controlled colloidal silica.

An attempt was made to control the surface charge of colloidal silica nanoparticles with 20 nm and 100 nm diameters. Untreated silica nanoparticles were determined to be highly negatively charged and have stable hydrodynamic sizes in a wide pH range. To change the surface to a positively charged form, various coating agents, such as amine containing molecules, multivalent metal cation, or amino acids, were used to treat the colloidal silica nanoparticles.

Isomorphous substitution of divalent metal ions in layered double hydroxides through a soft chemical hydrothermal reaction.

We have successfully incorporated Co(2+) ions into layered double hydroxides (LDHs) comprising Mg and Al hydroxides via isomorphous substitution utilizing a soft chemical hydrothermal reaction. The inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis showed that the incorporation of Co(2+) into an LDH was highly dependent on the dissolution of Mg(2+). The X-ray diffraction (XRD) patterns showed that the crystalline phase, as well as the crystallinity of pristine LDH, was well preserved without the evolution of impurities during the substitution reaction.

Pharmacokinetics, tissue distribution, and excretion of zinc oxide nanoparticles.

Background: This study explored the pharmacokinetics, tissue distribution, and excretion profile of zinc oxide (ZnO) nanoparticles with respect to their particle size in rats.

Methods: Two ZnO nanoparticles of different size (20 nm and 70 nm) were orally administered to male and female rats, respectively. The area under the plasma concentration-time curve, tissue distribution, excretion, and the fate of the nanoparticles in organs were analyzed.

Amorphous tungstate precursor route to nanostructured tungsten oxide film with electrochromic property.

Electrochromic tungsten oxide (WO3) films on ITO glass were fabricated by spin-coating with a tungsten peroxy acid solution, which was prepared by adding an equivolume mixture of hydrogen peroxide and glacial acetic acid to tungsten metal powder. The structural evolution of the tungstate precursor upon heat treatment was studied by X-ray diffraction (XRD) and X-ray absorption near edge structure (XANES) analyses, which indicated that the as-synthesized tungstate transformed into nanocrystalline WO3 upon heating. It is, therefore, quite clear that as-synthesized tungstate can be a good precursor for electrochromic WO3 films.

Surface passivation of CeO2 catalyst and its ultraviolet screening effect.

A new strategy was attempted to fabricate CeO2 nanoparticles using the surface fluorination technique to control the particle size and suppress the catalytic activity. The fluorinated CeO2 nanoparticles are fully characterized with XRD, XANES, UV-vis spectroscopy, HR-TEM, XPS along with the evaluation of photo and thermal catalytic activities. XRD patterns were not affected by surface fluorination.

Porous SnO2/layered titanate nanohybrid with enhanced electrochemical performance for reversible lithium storage.

A porous hybrid of titanate nanosheets with SnO(2) nanoparticles has been realized by an exfoliation and reassembling route. The present nanohybrid shows a large reversible capacity of 860 mA h g(-1) with a good capacity retention (about 60% retention of the initial capacity after 50 cycles).

A dual-polymer electrochromic device with high coloration efficiency and fast response time: poly(3,4-(1,4-butylene-(2-ene)dioxy)thiophene)-polyaniline ECD.

A new dual-polymer electrochromic device (ECD) composed of poly(3,4-(1,4-butylene-(2-ene)dioxy)thiophene) (PBueDOT) and polyaniline (PANI) with a hydrophobic molten salt electrolyte has been developed. To build this system, an alkylenedioxy ring in the BueDOT backbone was expanded to include a strongly electron-donating alkylenedioxy bridge, and the thickness and surface morphology of the corresponding PBueDOT film were controlled systematically. Not only the dual-electrochromic-polymer-electrode system, but also the expanded alkylenedioxy ring in the BueDOT backbone, synergistically improved the electrochromic performance.

A lattice-engineering route to heterostructured functional nanohybrids.

The fabrication of layered nanomaterials, such as inorganic-inorganic, organic-inorganic, and bioinorganic nanohybrids has been demonstrated through controlled lattice engineering techniques including intercalation, exfoliation-reassembling, and pillaring reactions. Such a lattice engineering method gives rise to an almost unlimited set of new hybrid compounds with a large spectrum of desirable properties. Due to the unique two-dimensional structures and properties, various kinds of functional nanohybrid materials can be utilized as photocatalysts, electrode materials, superconducting thin films, gas separation membranes, drug-delivery systems, and biomolecule reservoirs.

Dichlorido[(S)-N-(1-phenyl-ethyl-idene)-1-(pyridin-2-yl)ethanamine-κN,N']zinc(II) dichloro-methane solvate.

In the title compound, [ZnCl(2)(C(15)H(16)N(2))]·CH(2)Cl(2), the Zn(II) atom has a distorted tetra-hedral coordination by two Cl atoms and two N atoms from the organic ligand [the average Zn-N and Zn-Cl bond lengths are 2.060 (4) Å and Zn-Cl = 2.179 (16) Å, respectively].