How Surface and Substrate Chemistry Affect Slide Electrification.

When water droplets move over a hydrophobic surface, they and the surface become oppositely charged by what is known as slide electrification. This effect can be used to generate electricity, but the physical and especially the chemical processes that cause droplet charging are still poorly understood. The most likely process is that at the base of the droplet, an electric double layer forms, and the interfacial charge remains on the surface behind the three-phase contact line.

Solvothermal synthesis of VO nanoparticles with locally patched VO surface layer and their morphology-dependent catalytic properties for the oxidation of alcohols.

Vanadium oxides are promising oxidation catalysts because of their rich redox chemistry. We report the synthesis of VO nanocrystals with VO(B) crystal structure. By varying the mixing ratio of the components of a binary ethanol/water mixture, different VO nanocrystal morphologies (nanorods, -urchins, and -sheets) could be made selectively in pure form.

Bandgap Engineering of Melon using Highly Reduced Graphene Oxide for Enhanced Photoelectrochemical Hydrogen Evolution.

The uncondensed form of polymeric carbon nitrides (PCN), generally known as melon, is a stacked 2D structure of poly(aminoimino)heptazine. Melon is used as a photocatalyst in solar energy conversion applications, but suffers from poor photoconversion efficiency due to weak optical absorption in the visible spectrum, high activation energy, and inefficient separation of photoexcited charge carriers. Experimental and theoretical studies are reported to engineer the bandgap of melon with highly reduced graphene oxide (HRG).

Photoreforming of Waste Polymers for Sustainable Hydrogen Fuel and Chemicals Feedstock: Waste to Energy.

Energy from renewable resources is central to environmental sustainability. Among the renewables, sunlight-driven fuel synthesis is a sustainable and economical approach to produce vectors such as hydrogen through water splitting. The photocatalytic water splitting is limited by the water oxidation half-reaction, which is kinetically and energetically demanding and entails designer photocatalysts.

generation of HO using CaO as peroxide storage depot for haloperoxidase mimicry with surface-tailored Bi-doped mesoporous CeO nanozymes.

Designing the size, morphology and interfacial charge of catalyst particles at the nanometer scale can enhance their performance. We demonstrate this with nanoceria which is a functional mimic of haloperoxidases, a group of enzymes that halogenates organic substrates in the presence of hydrogen peroxide. These reactions in aqueous solution require the presence of HO.

Lithium confinement and dynamics in hexagonal and monoclinic tungsten oxide nanocrystals: a Li solid state NMR study.

Mixed-valence tungsten bronzes AWO (A = alkali metal, NH, .) are a series of compounds with adaptive structural and compositional features that make them a hot research topic in thermoelectrics, electrochromics, catalysis or energy applications in battery electrodes. The mixed hexagonal lithium ammonium bronze Li(NH)WO is a new member of this structural family whose properties are compared to those of the pure hexagonal tungsten bronze (NH)WO.

Communication Breakdown: Into the Molecular Mechanism of Biofilm Inhibition by CeO Nanocrystal Enzyme Mimics and How It Can Be Exploited.

Bacterial biofilm formation is a huge problem in industry and medicine. Therefore, the discovery of anti-biofilm agents may hold great promise. Biofilm formation is usually a consequence of bacterial cell-cell communication, a process called quorum sensing (QS).

Tuning ceria catalysts in aqueous media at the nanoscale: how do surface charge and surface defects determine peroxidase- and haloperoxidase-like reactivity.

Designing the shape and size of catalyst particles, and their interfacial charge, at the nanometer scale can radically change their performance. We demonstrate this with ceria nanoparticles. In aqueous media, nanoceria is a functional mimic of haloperoxidases, a group of enzymes that oxidize organic substrates, or of peroxidases that can degrade reactive oxygen species (ROS) such as HO by oxidizing an organic substrate.

Generalized synthesis of NaCrO particles for high-rate sodium ion batteries prepared by microfluidic synthesis in segmented flow.

NaCrO particles for high-rate sodium ion batteries were prepared on a multigram scale in segmented flow from chromium nitrate and sodium nitrate using a segregated flow water-in-oil emulsion drying process. Microfluidic processing is an environmentally friendly and rapid synthetic method, which can produce large-scale industrial implementation for the production of materials with superior properties. The reaction time for NaCrO particles was reduced by almost one order of magnitude compared to a normal flask synthesis and by several orders of magntitude compared to a conventional solid-state reaction.

Four-Step Spin Crossover in a New Cyano-Bridged Iron-Silver Coordination Polymer.

Spin-crossover complexes with multistep transitions attract much attention due to their potential applications as multi-switches and for data storage. A four-step spin crossover is observed in the new iron(II)-based cyanometallic guest-free framework compound Fe(2-ethoxypyrazine) {Ag(CN) } during the transition from the low-spin to the high-spin state. A reverse process occurs in three steps.

High-throughput synthesis of CeO nanoparticles for transparent nanocomposites repelling Pseudomonas aeruginosa biofilms.

Preventing bacteria from adhering to material surfaces is an important technical problem and a major cause of infection. One of nature's defense strategies against bacterial colonization is based on the biohalogenation of signal substances that interfere with bacterial communication. Biohalogenation is catalyzed by haloperoxidases, a class of metal-dependent enzymes whose activity can be mimicked by ceria nanoparticles.

Defect-controlled halogenating properties of lanthanide-doped ceria nanozymes.

Marine organisms combat bacterial colonization by biohalogenation of signaling compounds that interfere with bacterial communication. These reactions are catalyzed by haloperoxidase enzymes, whose activity can be emulated by nanoceria using milli- and micromolar concentrations of Br and HO. We show that the haloperoxidase-like activity of nanoceria can greatly be enhanced by Ln substitution in CeLnO.

In Vivo Biocompatibility Investigation of an Injectable Calcium Carbonate (Vaterite) as a Bone Substitute including Compositional Analysis via SEM-EDX Technology.

Injectable bone substitutes (IBS) are increasingly being used in the fields of orthopedics and maxillofacial/oral surgery. The rheological properties of IBS allow for proper and less invasive filling of bony defects. Vaterite is the most unstable crystalline polymorph of calcium carbonate and is known to be able to transform into hydroxyapatite upon contact with an organic fluid (e.

Advances in Graphene/Inorganic Nanoparticle Composites for Catalytic Applications.

Graphene-based nanocomposites with inorganic (metal and metal oxide) nanoparticles leads to materials with high catalytic activity for a variety of chemical transformations. Graphene and its derivatives such as graphene oxide, highly reduced graphene oxide, or nitrogen-doped graphene are excellent support materials due to their high surface area, their extended π-system, and variable functionalities for effective chemical interactions to fabricate nanocomposites. The ability to fine-tune the surface composition for desired functionalities enhances the versatility of graphene-based nanocomposites in catalysis.

1D iron(II)-1,2,4-triazolic chains with spin crossover assembled from discrete trinuclear complexes.

We report on a molecular cationic iron(II) complex with a 4-amino-1,2,4-triazole ligand and a tetraiodomercurate anion exhibiting an incomplete spin crossover (SCO). The complex exhibits an unusual disordered structure with a linear arrangement of ligand and water molecules that can potentially accommodate up to four iron atoms, but both terminal metal positions have half chemical occupancies, while occupancies of all ligands are full. This corresponds to the crystallisation of disordered trinuclear complexes arranged into 1D supramolecular chains.

Transparent polycarbonate coated with CeO nanozymes repel PA14 biofilms.

Highly transparent CeO/polycarbonate surfaces were fabricated that prevent adhesion, proliferation, and the spread of bacteria. CeO nanoparticles with diameters of 10-15 nm and lengths of 100-200 nm for this application were prepared by oxidizing aqueous dispersions of Ce(OH) with HO in the presence of nitrilotriacetic acid (NTA) as the capping agent. The surface-functionalized water-dispersible CeO nanorods showed high catalytic activity in the halogenation reactions, which makes them highly efficient functional mimics of haloperoxidases.

Magneli-type tungsten oxide nanorods as catalysts for the selective oxidation of organic sulfides.

Selective oxidation of thioethers is an important reaction to obtain sulfoxides as synthetic intermediates for applications in the chemical industry, medicinal chemistry and biology or the destruction of warfare agents. The reduced Magneli-type tungsten oxide WO possesses a unique oxidase-like activity which facilitates the oxidation of thioethers to the corresponding sulfoxides. More than 90% of the model system methylphenylsulfide could be converted to the sulfoxide with a selectivity of 98% at room temperature within 30 minutes, whereas oxidation to the corresponding sulfone was on a time scale of days.

Zinc Oxide Nanoparticles Can Intervene in Radiation-Induced Senescence and Eradicate Residual Tumor Cells.

Despite recent advancements in tumor therapy, metastasis and tumor relapse remain major complications hindering the complete recovery of many cancer patients. Dormant tumor cells, which reside in the body, possess the ability to re-enter the cell cycle after therapy. This phenomenon has been attributed to therapy-induced senescence.

Influence of Iron Sulfide Nanoparticle Sizes in Solid-State Batteries*.

Given the inherent performance limitations of intercalation-based lithium-ion batteries, solid-state conversion batteries are promising systems for future energy storage. A high specific capacity and natural abundancy make iron disulfide (FeS ) a promising cathode-active material. In this work, FeS nanoparticles were prepared solvothermally.

High-speed solid state fluorination of NbO yields NbOF and NbOF with photocatalytic activity for oxygen evolution from water.

Solid state reactions are slow because the diffusion of atoms or ions through the reactant, intermediate and crystalline product phases is the rate-limiting step. This requires days or even weeks of high temperature treatment, and consumption of large amounts of energy. We employed spark-plasma sintering, an engineering technique that is used for high-speed consolidation of powders with a pulsed electric current passing through the sample to carry out the fluorination of niobium oxide in minute intervals.

Determination of the LD with the chick embryo chorioallantoic membrane (CAM) assay as a promising alternative in nanotoxicological evaluation.

Toxicity tests in rodents are still considered a controversial topic concerning their ethical justifiability. The chick embryo chorioallantoic membrane (CAM) assay may offer a simple and inexpensive alternative. The CAM assay is easy to perform and has low bureaucratic hurdles.

Gram-scale selective synthesis of WO nanorods and (NH)WO ammonium tungsten bronzes with tunable plasmonic properties.

Localized surface plasmon resonance properties in unconventional materials like metal oxides or chalcogenide semiconductors have been studied for use in signal detection and analysis in biomedicine and photocatalysis. We devised a selective synthesis of the tungsten oxides WO and (NH)WO with tunable plasmonic properties. We selectively synthesized WO nanorods with different aspect ratios and hexagonal tungsten bronzes (NH)WO as truncated nanocubes starting from ammonium metatungstate (NH)HWO·xHO.

A Generalized Method for High-Speed Fluorination of Metal Oxides by Spark Plasma Sintering Yields Ta O F and TaO F with High Photocatalytic Activity for Oxygen Evolution from Water.

A general method to carry out the fluorination of metal oxides with poly(tetrafluoroethylene) (PTFE, Teflon) waste by spark plasma sintering (SPS) on a minute scale with Teflon is reported. The potential of this new approach is highlighted by the following results. i) The tantalum oxyfluorides Ta O F and TaO F are obtained from plastic scrap without using toxic or caustic chemicals for fluorination.

Three-Component Self-Assembly Changes its Course: A Leap from Simple Polymers to 3D Networks of Spherical Host-Guest Assemblies.

One-pot self-assembly reactions of the polyphosphorus complex [Cp*Fe(η -P )] (A), a coinage metal salt AgSbF , and flexible aliphatic dinitriles NC(CH ) CN (x=1-10) yield 1D, 2D, and 3D coordination polymers. The seven-membered backbone of the dinitrile was experimentally found as the borderline for the self-assembly system furnishing products of different kinds. At x<7, various rather simple polymers are exclusively formed possessing either 0D or 1D Ag/A structural motifs connected by dinitrile spacers, while at x≥7, the self-assembly switches to unprecedented extraordinary 3D networks of nano-sized host-guest assemblies (SbF )@[(A) Ag ] (x=7) or (A)@[(A) Ag ] (x=8-10) linked by dinitriles.