Discover Top Posts Tagged with #core shell structures

This Paint Changes Colors When Hit. The Uses Are Striking

A new impact-revealing coating can measure forces from the light to the powerful

Newswise — Imagine a paint that changes color depending on how hard its surface is hit. It could be used on football helmets to monitor concussion-level impacts, to record the handling history of shipped packages, or placed on insoles to analyze an orthopedic patient’s gait. The paint is the latest innovation coming from the Tufts University Silklab, led by Fiorenzo Omenetto, Frank C. Doble Professor of Engineering. Omenetto and research assistant professors Marco Lo Presti and Giulia Guidetti developed the paint to quantitatively measure the site and force of an impact without using any electronic circuitry or sensors. The innovative substance is made with a color‑changing polymer surrounded by a silk protein polymer shell, and can be painted on surfaces of almost any size, texture, or contour. The potential applications cover a wide range of measurements, from the subtle changes in pressure when analyzing the surface aerodynamics of cars and planes to the powerful impacts that could occur from military or industrial blast exposure.

3D-printed nozzle array could streamline production of drug-delivery microparticles

MIT researchers have demonstrated a low-cost design for specialized electronic nozzles, called triaxial electrospray emitters, that could be used to manufacture time-release drug-delivery particles or self-healing materials efficiently and at scale. Triaxial electrospray emitters use electricity to precisely dispense three liquids from microscopic nozzles to generate a steady stream with three distinct fluid layers. The liquid forms multilayered droplets, which can solidify into layered microparticles. For instance, an array of triaxial electrospray emitters can be used to make three-layer drug-delivery nanoparticles. The outer layer might slowly erode in the stomach, revealing a second material that controls the release of a core material, which delivers medicine to a specific area of the intestines.

Sprinkling nanoparticles on spintronics

Today, I want to walk you through a deceptively simple innovation from the lab at Loughborough University (PI: Prof Marco Peccianti): what happens when we decorate a spintronic heterostructure with a sparse layer of plasmonic nanoparticles? This isn't just a lab curiosity—it's a step toward making terahertz sources more efficient, compact, and practical for real-world applications like high-speed communications, noninvasive imaging, and advanced spectroscopy. Spintronic THz emitters: The foundation Spintronic terahertz emitters rely on a thin, multilayer stack—typically heavy metal like tungsten (W), a ferromagnetic layer such as iron (Fe), and a platinum (Pt) cap. A femtosecond laser pulse strikes the structure, rapidly heating electrons and generating a pure spin current through spin-orbit torque effects.

Iron core-shell catalyst boosts hydrogen economy of direct syngas to olefin conversion

Scientists have developed a new iron-based catalyst that improves the typically low hydrogen atom economy (HAE) in the direct synthesis of olefins—small hydrocarbon molecules. It converts the water produced as a by-product into hydrogen for olefin production, thereby boosting overall efficiency. Olefins derived from petroleum are the building blocks for many plastics and fuels. Direct conversion of syngas—a mixture of carbon monoxide (CO) and hydrogen (H2)—into olefins offers a promising alternative to reducing reliance on petroleum. It opens ways for using syngas derived from coal, biomass, or natural gas as a feedstock for olefin production. In this study published in Science, researchers presented a sodium-modified FeCx@Fe3O4 core-shell catalyst produced via coprecipitation and thermal treatment. The catalyst achieved over 75% olefin selectivity and a 33% by weight hydrocarbon yield. It also had an HAE of ~66–86%, which is significantly higher than the ~43–47% seen in the traditional syngas-to-olefin (STO) conversion methods.

Metallic nanocatalysts: What really happens during catalysis

Using a combination of spectromicroscopy at BESSY II and microscopic analyses at DESY's NanoLab, a team has gained new insights into the chemical behavior of nanocatalysts during catalysis. The research is published in the journal ACS Nano. The nanoparticles consisted of a platinum core with a rhodium shell. This configuration allows a better understanding of structural changes in, for example, rhodium–platinum catalysts for emission control. The results show that under typical catalytic conditions, some of the rhodium in the shell can diffuse into the interior of the nanoparticles. However, most of it remains on the surface and oxidizes. This process is strongly dependent on the surface orientation of the nanoparticle facets. Nanoparticles measure less than one ten-thousandth of a millimeter in diameter and have enormous surface areas in relation to their mass. This makes them attractive as catalysts: metallic nanoparticles can facilitate chemical conversions, whether for environmental protection, industrial synthesis or the production of (sustainable) fuels from CO2 and hydrogen.

Novel nanowire catalyst could help advance hydrogen production technology

Researchers at Beijing University of Technology have developed a new type of acid-stable bimetallic phosphide-silver core-shell nanowire catalyst that significantly improves the efficiency of the hydrogen evolution reaction (HER). Their findings, published in Frontiers in Energy, offer promising insights into advancing hydrogen production technologies. Hydrogen production through proton exchange membrane water electrolysis is a crucial step toward sustainable energy solutions. However, the development of cost-effective and efficient electrocatalysts that can withstand acidic conditions remains a significant challenge. Traditional non-noble metal catalysts often fall short in performance and durability when exposed to harsh acidic environments.

High heat dissipation design improves thermal protection on ultrahigh temperature ablation

ZrC has drawn wide attention as an anti-ablation coating material for lightweight C/C composites but is limited by the produced porous and loose ZrO2 film. To address this issue, the second phase is introduced to improve the densification of the formed Zr-X-O film. Such as ZrC-SiC/TaC coating, the produced low-melting-point oxides, SiO2 (Tm=1650 °C), Ta2O5 (Tm=1800 °C) and Zr6Ta2O17 (Tm=1900 °C), helped to form a dense oxides film. However, the high service temperature causes heat accumulation and a large thermal stress gradient on the surface of the coatings, which will result in large local defects and accelerate the failure of the coating.

Core-shell structural units show outstanding toughening effect for ceramics

Toughening has always been an important research direction of structure ceramics. The addition of secondary phases to the ceramic matrix to prepare composite ceramics is an effective toughening pathway in the field of structure ceramics. Both phase-type and microstructure of the secondary phases play a decisive role in the toughening effect of the ceramic matrix. Being different from the conventional independent phase as the secondary phase, B4C@TiB2 core–shell structural unit has been purposely designed as an innovative kind of secondary phase to toughen the Al2O3 ceramic matrix, providing a new concept for the toughening studies of structural ceramics. A team of material scientists led by Zhixiao Zhang from the Hebei University of Engineering in Handan, China recently successfully prepared a kind of Al2O3 composite ceramics toughened by B4C@TiB2 core–shell structural units consisting of the B4C core enclosed by the TiB2 shell.

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