Chain-Like Semiconductive Fillers for Dielectric Enhancement and Loss Reduction of Polymer Composites.

Dielectric loss is a crucial factor in determining the long-term endurance for security and energy loss of dielectric composites. Here, chain-like semiconductive fibers of titanium oxide, indium, and niobium-doped titanium oxide are used for enhancing the complex dielectric properties of a polymer through composite construction, which involves significant interface enhancements. The chain-like fibers significantly enhance the dielectric constant owing to the special morphology of the fillers and their interfacial polarization, especially at higher temperatures.

Carbon Contamination Prevention during Spark Plasma Sintering.

Carbon contamination from graphite molds during spark plasma sintering (SPS) considerably affects the properties of the sintered materials, especially transparent ceramics. Herein, transparent YAlO (YAG) ceramics were prepared via SPS using Mo and Ta foils, separately and in tandem, as protective barriers against carbon contamination. The effects of Ta and Mo foils on the transparency and microstructure of the ceramics, and their protection mechanisms were studied.

Highly Transparent Polycrystalline MgO via Spark Plasma Sintering.

Optically transparent ceramics and MgO in particular are promising materials for a wide range of optical applications. This study introduces exceptionally highly transparent MgO ceramics produced via spark plasma sintering (SPS) at relatively low temperature and pressure by optimal incorporation of LiF as a sintering additive. The effect of LiF content on the microstructural and optical properties is presented with emphasis on its function as a densification aid and an agent for minimizing residual carbon contamination.

Composite Indium Tin Oxide Nanofibers with Embedded Hematite Nanoparticles for Photoelectrochemical Water Splitting.

Hematite is a classical photoanode material for photoelectrochemical water splitting due to its stability, performance, and low cost. However, the effect of particle size is still a question due to the charge transfer to the electrodes. In this work, we addressed this subject by the fabrication of a photoelectrode with hematite nanoparticles embedded in close contact with the electrode substrate.

Metal nanoparticles entrapped in metal matrices.

We developed synthetic methods for the doping of metals (M) with metallic nanoparticles (NPs). To the best of our knowledge - unlike oxides, polymers and carbon-based supports - metals were not used so far as supporting matrices for metallic NPs. The composites (denoted M1-NPs@M2) comprise two separate phases: the metallic NPs (the dopant) and the entrapping 3D porous metallic matrix, within which the NPs are intimately held and well dispersed.

Electrospun nanofibers with surface oriented lamellar patterns and their potential applications.

This work shows conclusively that lamellar surface patterns can be obtained with diverse ceramic compositions during electrospinning. The lamellar structure formation is governed by the creation of an outer shell during the thermal treatment of initially uniform cylindrical fibers, consisting of polymer and pre-ceramic compounds. By changing the polymer to pre-ceramic ratio in the electrospinning solution, we demonstrate for the first time a facile way to control the obtained surface structure and the orientation of the lamellas.

Progress and Prospective of Nitrogen-Based Alternative Fuels.

Alternative fuels are essential to enable the transition to a sustainable and environmentally friendly energy supply. Synthetic fuels derived from renewable energies can act as energy storage media, thus mitigating the effects of fossil fuels on environment and health. Their economic viability, environmental impact, and compatibility with current infrastructure and technologies are fuel and power source specific.

Electrospun Fe-Al-O Nanobelts for Selective CO Hydrogenation to Light Olefins.

Ceramic nanobelt catalysts consisting of Fe-Al-O spinel modified with potassium were synthesized for CO hydrogenation into hydrocarbons. Nanobelts and hollow nanofibers were produced utilizing the internal heat released by oxidation of the organic component within the fibers. This extremely fast and short heating facilitated crystallization of the desired phase, while maintaining small grains and a large surface area.

Electrospun Anion-Conducting Ionomer Fibers-Effect of Humidity on Final Properties.

Anion-conducting ionomer-based nanofibers mats are prepared by electrospinning (ES) technique. Depending on the relative humidity (RH) during the ES process (RH), ionomer nanofibers with different morphologies are obtained. The effect of relative humidity on the ionomer nanofibers morphology, ionic conductivity, and water uptake (WU) is studied.

Lamellar-like Electrospun Mesoporous Ti-Al-O Nanofibers.

Ceramic oxides nanofibers are promising materials as catalysts, electrodes and functional materials. In this report, a unique lamellar-like mesoporous structure was realized for the first time in a new system based on titania and alumina. The final structure was found to be highly dependent on the process conditions which are outlined herein.

Pollutant Abatement of Nitrogen-Based Fuel Effluents over Mono- and Bimetallic Pt/Ru Catalysts.

Mono- and bimetallic alloy Pt and Ru catalysts supported on γ-AlO have been investigated for the reduction of pollutants (NO , NH, and CO) generated during the continuous combustion of an aqueous urea ammonium nitrate fuel. A Pt/Ru alloy with a Pt25/Ru75 atomic ratio has been found to have higher activity and selectivity than those of a 50/50 alloy and monometallic catalysts. Among monometallic catalysts, Ru was more selective toward N formation, whereas Pt showed a higher selectivity toward NH formation.

Photoelectrochemical water splitting in separate oxygen and hydrogen cells.

Solar water splitting provides a promising path for sustainable hydrogen production and solar energy storage. One of the greatest challenges towards large-scale utilization of this technology is reducing the hydrogen production cost. The conventional electrolyser architecture, where hydrogen and oxygen are co-produced in the same cell, gives rise to critical challenges in photoelectrochemical water splitting cells that directly convert solar energy and water to hydrogen.

Nitrogen-Based Fuels: A Power-to-Fuel-to-Power Analysis.

What are the fuels of the future? Seven representative carbon- and nitrogen-based fuels are evaluated on an energy basis in a power-to-fuel-to-power analysis as possible future chemical hydrogen-storage media. It is intriguing to consider that a nitrogen economy, where hydrogen obtained from water splitting is chemically stored on abundant nitrogen in the form of a nontoxic and safe nitrogen-based alternative fuel, is energetically feasible.