Nitration-Promoted Vanadate Catalysts for Low-Temperature Selective Catalytic Reduction of NO with NH.

Vanadium-based catalysts have been commercially used in selective catalytic reduction (SCR), owing to their high catalytic activity and effectiveness across a wide temperature range; however, their catalytic efficiency decreases at lower temperatures under exposure to SO. This decrease is largely due to ammonium sulfate generation on the catalyst surface. To overcome this limitation, we added ammonium nitrate to the VO-WO/TiO catalyst, producing a VO-WO/TiO catalyst with nitrate functional groups.

Cl- and Al-Doped Argyrodite Solid Electrolyte LiPSCl for All-Solid-State Lithium Batteries with Improved Ionic Conductivity.

Argyrodite solid electrolytes such as lithium phosphorus sulfur chloride (LiPSCl) have recently attracted great attention due to their excellent lithium-ion transport properties, which are applicable to all-solid-state lithium batteries. In this study, we report the improved ionic conductivity of an argyrodite solid electrolyte, LiPSCl, in all-solid-state lithium batteries via the co-doping of chlorine (Cl) and aluminum (Al) elements. Electrochemical analysis was conducted on the doped argyrodite structure of LiPSCl, which revealed that the substitution of cations and anions greatly improved the ionic conductivity of solid electrolytes.

Hybrid Carbon Supports Composed of Small Reduced Graphene Oxide and Carbon Nanotubes for Durable Oxygen Reduction Catalysts in Proton Exchange Membrane Fuel Cells.

We demonstrated highly active and durable hybrid catalysts (HCs) composed of small reduced graphene oxide (srGO) and carbon nanotubes (CNTs) for use as oxygen reduction reaction (ORR) catalysts in proton exchange membrane fuel cells. Pt/srGO and Pt/CNTs were prepared by loading Pt nanoparticles onto srGO and CNTs using a polyol process, and HCs with different Pt/CNT and Pt/srGO ratios were prepared by mechanically mixing the two components. The prepared HCs consisted of Pt/CNTs well dispersed on Pt/srGO, with catalyst HC55, which was prepared using Pt/srGO and Pt/CNTs in a 5:5 ratio, exhibiting excellent oxygen reduction performance and high stability over 1000 cycles of the accelerated durability test (ADT).

Polyol-Mediated Synthesis of VO-WO/TiO Catalysts for Low-Temperature Selective Catalytic Reduction with Ammonia.

We demonstrated highly efficient selective catalytic reduction catalysts by adopting the polyol process, and the prepared catalysts exhibited a high nitrogen oxide (NO) removal efficiency of 96% at 250 °C. The VO and WO catalyst nanoparticles prepared using the polyol process were smaller (~10 nm) than those prepared using the impregnation method (~20 nm), and the small catalyst size enabled an increase in surface area and catalytic acid sites. The NO removal efficiencies at temperatures between 200 and 250 °C were enhanced by approximately 30% compared to those of the catalysts prepared using the conventional impregnation method.

Small Reduced Graphene Oxides for Highly Efficient Oxygen Reduction Catalysts.

We demonstrated highly efficient oxygen reduction catalysts composed of uniform Pt nanoparticles on small, reduced graphene oxides (srGO). The reduced graphene oxide (rGO) size was controlled by applying ultrasonication, and the resultant srGO enabled the morphological control of the Pt nanoparticles. The prepared catalysts provided efficient surface reactions and exhibited large surface areas and high metal dispersions.

Rapid and Robust Surface Treatment for Simultaneous Solid and Liquid Repellency.

A wide range of liquid and solid contaminants can adhere to everyday functional surfaces and dramatically alter their performance. Numerous surface modification strategies have been developed that can reduce the fouling of some solids or repel certain liquids but are generally limited to specific contaminants or class of foulants. This is due to the typically distinct mechanisms that are employed to repel liquids vs solids.

Ammonium Ion Enhanced VO-WO/TiO Catalysts for Selective Catalytic Reduction with Ammonia.

Selective catalytic reduction (SCR) is the most efficient NO removal technology, and the vanadium-based catalyst is mainly used in SCR technology. The vanadium-based catalyst showed higher NO removal performance in the high-temperature range but catalytic efficiency decreased at lower temperatures, following exposure to SO because of the generation of ammonium sulfate on the catalyst surface. To overcome these limitations, we coated an NH layer on a vanadium-based catalyst.

Effect of Catalyst Crystallinity on V-Based Selective Catalytic Reduction with Ammonia.

In this study, we synthesized VO-WO/TiO catalysts with different crystallinities via one-sided and isotropic heating methods. We then investigated the effects of the catalysts' crystallinity on their acidity, surface species, and catalytic performance through various analysis techniques and a fixed-bed reactor experiment. The isotropic heating method produced crystalline VO and WO, increasing the availability of both Brønsted and Lewis acid sites, while the one-sided method produced amorphous VO and WO.

Selective Wettability Membrane for Continuous Oil-Water Separation and In Situ Visible Light-Driven Photocatalytic Purification of Water.

Membrane-based technologies are attractive for remediating oily wastewater because they are relatively energy-efficient and are applicable to a wide range of industrial effluents. For complete treatment of oily wastewater, removing dissolved contaminants from the water phase is typically followed by adsorption onto an adsorbent, which complicates the process. Here, an in-air superhydrophilic and underwater superoleophobic membrane-based continuous separation of surfactant-stabilized oil-in-water emulsions and in situ decontamination of water by visible-light-driven photocatalytic degradation of dissolved organic contaminants is reported.

Synthesis of oxygen functionalized carbon nanotubes and their application for selective catalytic reduction of NO with NH.

Oxygen functionalized carbon nanotubes synthesized by surface acid treatment were used to improve the dispersion properties of active materials for catalysis. Carbon nanotubes have gained attention as a support for active materials due to their high specific surface areas (400-700 m g) and chemical stability. However, the lack of surface functionality causes poor dispersion of active materials on carbon nanotube supports.

Foldable water-activated reserve battery with diverse voltages.

A reserve battery is a device which is inert until its activation and generates electricity by injecting an electrolyte for the purpose of immediate use. Due to a relatively short history and the use in restricted fields, reserve batteries have not attracted attention without any technical advance such as be being flexible and foldable. In this study, we demonstrate a way of fabricating a flexible and even foldable reserve battery which is activated by various solutions.

Self-Healable Superomniphobic Surfaces for Corrosion Protection.

Corrosion-protective surfaces are of the utmost relevance to ensure long-term stability and reliability of metals and alloys by limiting their interactions with corrosive species, such as water and ions. However, their practical applications are often limited either by the inability to repel low surface tension liquids such as oils and alcohols or by poor mechanical durability. Here, a superomniphobic surface is reported that can display very high contact angles for both high and low surface tension liquids as well as for concentrated acids and bases.

Enhanced NO removal efficiency for SCR catalyst of well-dispersed Mn-Ce nanoparticles on hexagonal boron nitride.

This research is conducted to improve the dispersion of MnO-CeO catalyst because manganese is easily aggregated during continuous thermal environment at operating temperature. Aggregated MnO particles on the support can be a major reason to degrade the catalyst performance. Therefore, the improved dispersion of MnO particles leads to the enhancement of the catalyst performance by utilizing hexagonal boron nitride (h-BN) which is well known as thermally stable material.

Rational Design of Hyperbranched Nanowire Systems for Tunable Superomniphobic Surfaces Enabled by Atomic Layer Deposition.

Superomniphobic surfaces display contact angles of θ* > 150° and low contact angle hysteresis with virtually all high and low surface tension liquids. The introduction of hierarchical scales of texture can increase the contact angles and decrease the contact angle hysteresis of superomniphobic surfaces by reducing the solid-liquid contact area. Thus far, it has not been possible to fabricate superomniphobic surfaces with three or more hierarchical scales of texture where the size, spacing, and angular orientation of features within each scale of texture can be independently varied and controlled.

Designing durable icephobic surfaces.

Ice accretion has a negative impact on critical infrastructure, as well as a range of commercial and residential activities. Icephobic surfaces are defined by an ice adhesion strength τice < 100 kPa. However, the passive removal of ice requires much lower values of τice, such as on airplane wings or power lines (τice < 20 kPa).

Wettability engendered templated self-assembly (WETS) for fabricating multiphasic particles.

Precise control over the geometry and chemistry of multiphasic particles is of significant importance for a wide range of applications. In this work, we have developed one of the simplest methodologies for fabricating monodisperse, multiphasic micro- and nanoparticles possessing almost any composition, projected shape, modulus, and dimensions as small as 25 nm. The synthesis methodology involves the fabrication of a nonwettable surface patterned with monodisperse, wettable domains of different sizes and shapes.

Extreme light absorption by multiple plasmonic layers on upgraded metallurgical grade silicon solar cells.

We fabricate high-efficiency, ultrathin (∼12 μm), flexible, upgraded metallurgical-grade polycrystalline silicon solar cells with multiple plasmonic layers precisely positioned on top of the cell to dramatically increase light absorption. This scalable approach increases the optical absorptivity of our solar cells over a broad range of wavelengths, and they achieve efficiencies η ≈ 11%. Detailed studies on the electrical and optical properties of the developed solar cells elucidate the light absorption contribution of each individual plasmonic layer.

High efficiency thin upgraded metallurgical-grade silicon solar cells on flexible substrates.

We present a thin film (<20 μm) solar cell based on upgraded metallurgical-grade polycrystalline Si that utilizes silver nanoparticles atop silicon nanopillars created by block copolymer nanolithography to enhance light absorption and increase cell efficiency η > 8%. In addition, the solar cells are flexible and semitransparent so as to reduce balance of systems costs and open new applications for conformable solar cell arrays on a variety of surfaces. Detailed studies on the optical and electrical properties of the resulting solar cells suggest that both antireflective and light-trapping mechanisms are key to the enhanced efficiency.

Mussel-inspired block copolymer lithography for low surface energy materials of teflon, graphene, and gold.

Mussel-inspired interfacial engineering is synergistically integrated with block copolymer (BCP) lithography for the surface nanopatterning of low surface energy substrate materials, including, Teflon, graphene, and gold. The image shows the Teflon nanowires and their excellent superhydrophobicity.

Theory, synthesis, and oxygen reduction catalysis of Fe-porphyrin-like carbon nanotube.

We report the synthesis of a Fe-porphyrin-like carbon nanotube from conventional plasma-enhanced chemical vapor deposition. Covalent but seamless incorporation of the 5-6-5-6 porphyrinic Fe-N(4) moiety into the graphene hexagonal side wall was elucidated by x-ray and ultraviolet photoemission spectroscopies and first-principles electronic structure calculations. The resulting biomimetic nanotube exhibits an excellent oxygen reduction catalytic activity with the extreme structural stability over 0.

Flexible field emission of nitrogen-doped carbon nanotubes/reduced graphene hybrid films.

The outstanding flexible field emission properties of carbon hybrid films made of vertically aligned N-doped carbon nanotubes grown on mechanically compliant reduced graphene films are demonstrated. The bottom-reduced graphene film substrate enables the conformal coating of the hybrid film on flexible device geometry and ensures robust mechanical and electrical contact even in a highly deformed state. The field emission properties are precisely examined in terms of the control of the bending radius, the N-doping level, and the length or wall-number of the carbon nanotubes and analyzed with electric field simulations.

Biomimetic mineralization of vertical N-doped carbon nanotubes.

Biomimetic mineralization of vertical N-doped carbon nanotubes is demonstrated as a straightforward route for carbon-based mineral nanocomposites. The N-doped sites along the carbon nanotube backbone play the role of nucleation sites for mineralization.

Surface energy modification by spin-cast, large-area graphene film for block copolymer lithography.

We demonstrate a surface energy modification method exploiting graphene film. Spin-cast, atomic layer thick, large-area reduced graphene film successfully played the role of surface energy modifier for arbitrary surfaces. The degree of reduction enabled the tuning of the surface energy.